Department of Aromatherapy

We offer a full range of Aromatherapy Certificates, diplomas, and Degree Plans!

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What is Aromatherapy?

When you break up the word “aromatherapy,” you get:

  • aroma = a noticeable, oftentimes pleasant smell.
  • therapy = from the Greek therapeia “healing;” to minister to.

So, translated literally, “aromatherapy” is the use of aromas for their therapeutic properties.

As aromatherapy as a healing modality has evolved, it has taken on a wide range of definitions, perspectives, and applications. Today, aromatherapy is known as the use of aromatic plant materials in the form of essential oils and extracts to support and promote the balance of physical, mental, emotional, and spiritual health.

“Memories, imagination, old sentiments, and associations are more readily reached through the sense of smell than through any other channel.” – Oliver Wendell Holmes



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Frequently Asked Questions

Why Choose Our Accredited Aromatherapy Courses

At American College of Healthcare Sciences (ACHS), we focus on “holistic aromatology,” the idea that optimal wellbeing is achieved by recognizing the individual and addressing the whole person: body, mind, and spirit.

We use the terms “aromatherapy” and “aromatology” interchangeably in our online courses, but we wanted to provide the distinctive definition to give you a better understanding of how it may be used elsewhere.

Learn more about the basic concepts of holistic aromatherapy in this free eBook, Aromatherapy Everyday Basics.

You’ll find professional aromatherapists working in a number of industries like…

  • Perfumery & flavoring
  • Natural products & cosmetics
  • Hospital & clinical settings
  • Private in-person & telehealth wellness consulting
  • Spa & hospitality
  • Thought leadership & education

Working professionals such as nurses, doctors, chiropractors, massage therapists, and herbalists often integrate aromatherapy into their practice to offer a more well-rounded, holistic client experience.

As essential oils become more and more popular, there is a growing need for experts in many industries! Wherever your love of essential oils and wellness may lead you, it’s best to begin with an industry-celebrated, quality education in aromatherapy.

The Future of Professional Aromatherapy

As we’ve covered above, a number of industries are beginning to utilize aromatherapy. The global essential oil market is steadily increasing and projected to reach USD 13.94 billion by 2024![1]

And as essential oils become even more embedded into everyday life, the need for expertise continues to grow.

If your goal is to become a professional aromatherapist who works with clients, there are a few key facts to keep in mind. (FYI – we cover these topics in even more depth in our accredited online aromatherapy courses.)

Health Freedom

First, if you want to be an aromatherapist in a state without Health Freedom legislation, you must be aware of your limitations to avoid violating medical practice acts. ACHS covers the differences between medical professionals and health coaches and health educators, among others, in NAT 306 Holistic Health Consulting and Business Skills Online.

The Role of the Professional Aromatherapist

When working with clients, a professional aromatherapist always defines their role clearly. Many professionals use a statement like the one below to provide clarity and transparency to clients. It can be posted as a notice in your office, sent in an email, or given as a pamphlet. You may even provide a “role of the client” fact sheet so everyone has a well-defined understanding of the services provided in your aromatherapy sessions.

A professional aromatherapist coaches and educates clients on how to achieve and sustain wellness through the safe use of high-quality essential oils. They encourage and teach clients to follow the fundamentals of good health, like the importance of holistic living through fresh air, clean water, whole-foods nutrition, exercise, and healthy lifestyle choices.

An aromatherapist performs evaluations to determine causes of potential health problems and imbalanced body systems, and will always refer a client back to their primary care physician for a diagnosis if necessary.

A professional aromatherapist DOES NOT diagnose or treat disease, prescribe drugs or pharmaceuticals, or perform invasive procedures like surgery or other touch therapies that they are not licensed to perform.

[1] Petersen, D. (2017). Careers in aromatherapy. [White paper]. Retrieved from

Essential oils have many ways of promoting personal wellbeing. A good place to start is to understand the essential concepts of essential oil blending.

Blending essential oils is all about inhaling! For those of you who are brand new to essential oils and aromatherapy, one of the best ways to begin creating personal fragrances is by experimenting with combining essential oils that you love from the very first inhale. 

You can then experiment with using your blends in diffusers, soaps, and room and body sprays. While this is a fun and creative process, blending essential oils is an art and science that takes a bit of skill and knowledge. It’s helpful to have a few tools in your toolbox when creating your perfect essential oil blend. 

With that in mind, this blog post provides an overview of essential oil blending and aromatherapy fundamentals. But if aromatherapy fragrance blending with essential oils is a serious topic of interest for you, this blog post on creating successful aromatherapy blends goes into more depth. There are also a lot of excellent books and classes you can take, including ACHS’s on-demand course, Basic Blending with Essential Oils, and the accredited online course, AROMA 101: Introduction to Aromatherapy course.

Now that you understand the basic concepts of essential oil blending, the fun starts!

If there’s one topic that is crucial to the practice of aromatherapy, it’s essential oil safety. This topic can quickly get heated on social media, web forums, and elsewhere within the aromatherapy community. With all the misinformation out there, this is no surprise.

Some of the most common questions we get at ACHS are:

While there are many opinions and approaches to using essential oils safely, here are a few key resources to help you feel confident as you dive into aromatherapy.

We suggest starting off with our popular eBook, Essentials of Essential Oil Safety.

You’ll learn…

  • 5 key concepts for essential oil safety
  • How to safely use essential oils in the bath
  • How quality affects therapeutic value and safety
  • Essential oil safety guidelines and common mistakes
  • What is photosensitivity?

There are many opinions and approaches to how aromatherapy can be practiced safely and effectively. There’ve been heated debates over whether essential oils should ever be used neat (without dilution), whether they are safe to ingest, and even how they should be safely used in the bathtub.

To start, let’s quickly define 6 key safety concepts that you should know as an aromatherapist or essential oil enthusiast:

#1 Celebrate the Individual!

Aromatherapists must honor individual composition. As we often repeat in the holistic health industry, everyone is an individual. So, it’s important to recognize that each person has a unique metabolism, vitality, and physical makeup.

#2 Low Therapeutic Margin

Have you heard the saying, natural doesn’t mean non-toxic? This is true. Plants are powerful, which is why it’s important to know how much of an essential oil or herb is beneficial, and how much is toxic. You’ll hear the term low therapeutic margin used in both aromatherapy and herbal medicine. What this means is that the difference between a therapeutic dose and a harmful dose is a very small amount.

Even popular oils can have a low therapeutic margin, like basil Ocimum basilicum (L.) and clove Syzygium aromaticum (L.), and they should be used with caution.

The important thing to remember about these plants: the difference between a helpful dose and a harmful dose can be mere drops! Less is more.

Learn more about low therapeutic margin in this blog post here.

#3 Toxicity

Understanding toxicity is key to practicing aromatherapy safely. Essential oils with a low therapeutic margin often have a high toxicity rating. This depends on the constituent profile (chemical makeup) of the oil. Most often, a toxic reaction is due to incorrect dosage or administration. So, before you start using oils with a toxic rating, be sure to …

  • Learn the therapeutic margin
  • Check the Recommended Daily Dose (RDD)
  • Perform a skin patch test
  • Never use if pregnant or breastfeeding
  • Never administer to children, infants, elderly, or those who are frail with weakened immunity 

There are a few ways that a toxic reaction can manifest in the body, and we’ll define those below.

#4 Skin Irritation

Some oils can cause irritation if you use them undiluted. Essentially, skin irritation is the result of contact with an abrasive substance. It is localized, and the extent of the irritation depends on how much of the substance was used. As we mentioned, always confirm the RDD and follow those instructions exactly when using essential oils. If you’re a sensitive person or working with an essential oil with a low therapeutic margin, do a skin patch test to check for any irritation. 

To avoid skin irritation, make sure your essential oils are correctly diluted with a carrier oil (also called a base oil). In general, we suggest avoiding using “neat” (direct/undiluted) essential oils on the skin. Start by erring on the side of caution. Begin with a high dilution ratio — we recommend 24 drops in four ounces of carrier oil (or 1%).

It’s worth repeating: when it comes to aromatherapy, less is more! 

If your skin gets irritated, bathe the affected area with a carrier oil or full-fat milk. Remember, oil and water do not mix, so using a nonpolar substance like milk or oil is the best way to wash off the essential oil.

#5 Skin Sensitization

Sensitization is not irritation, although these terms are often confused. Let’s look at the definition of sensitization.

Sensitization is a systemic response involving the immune system. This reaction happens once the culprit essential oil has absorbed into the skin, and has been flagged by the body’s immune system. This reaction does not always occur on the first exposure to an essential oil, and can develop over time.

There’s a dangerous myth that claims essential oils do not cause allergic reactions because they do not contain larger molecules, such as amino acids and proteins. This is false, and you can learn why in this blog post here.

If an allergic reaction occurs, remove the essential oil with full-fat milk or a carrier oil, and stop using it.

We’d love to believe that all essential oils are pure, undiluted, and grown without pesticides or harmful chemicals, but that’s just not reality. Not all essential oils are created equal!

Many factors affect the quality and therapeutic benefits of essential oils. It’s important to keep these factors in mind when assessing quality:

  • Where/how was the plant grown?
  • What part of the plant was used/should have been used to distill the oil?
  • What is the climate of where the plant was grown?
  • How/when was the plant harvested?
  • How was the essential oil produced?
  • How was the essential oil stored after distillation?

As you’re learning, essential oil quality directly affects safety and therapeutic efficacy. Learn more about why quality matters and how to check the quality of your essential oils in this blog post here.

To support consistency and safety in our classrooms, ACHS students use organic and sustainably wildcrafted essential oils from the college store, the Apothecary Shoppe.

The Apothecary Shoppe’s core mission is to provide students, graduates, and the public with the highest quality natural products possible. At the Apothecary Shoppe, you can shop with confidence knowing that ACHS President and Founder Dorene Petersen has hand-selected each and every product and had it carefully tested and assessed by trained Apothecary Shoppe staff.

To learn more about quality at the Apothecary Shoppe, check out the Quality Promise here.

There are many options out there for you to study aromatherapy. NAHA and AIA are excellent resources when researching aromatherapy schools. Both of these organizations require their “recognized” schools to meet approved standards for aromatherapy education.

You can view NAHA’s approved schools here, and AIA’s approved schools here.

While you research skills, keep in mind that choosing a school and aromatherapy program is ultimately a personal decision. Ask yourself, do you want to study online or in-person? Do you want to work at your own pace? Do you value interaction with a live professor? Do you want to attend an accredited school? Ultimately, your choice depends on your goals and the type of educational experience that works for you.

As the digital world grows, more and more subjects can be studied online without any disadvantage. Aromatherapy is one of them!

You may wonder: how can I study and experience essential oils from my computer? At ACHS, there are a few ways we make studying aromatherapy online as dynamic and interactive as if you were in a brick-and-mortar classroom:

  • Course assignments require the use of hands-on lab kits including certified organic essential oils, among other items.
  • All students are required to use the same course lab kits, which ensures all students are working with certified organic or sustainably produced, tested, and verified raw materials from the same source and are following ARC’s safety protocols for administration.
  • ACHS professors may conduct weekly live lessons through a video conference tool, Zoom.
  • Online classrooms include interactive discussion boards where you can work side-by-side with your classmates.
  • Professors are industry experts with a passion for teaching and active in the classroom six days per week

Accreditation is a process by which educational institutions are evaluated by a third party (an approved accrediting body) to determine if the school meets set educational and business standards. ACHS is accredited by the Distance Education Accrediting Commission (DEAC), which is recognized by the U.S. Department of Education and by the Council for Higher Education Accreditation (CHEA).

You might be wondering, who cares if my school is accredited or not? As long as they provide a good program, isn’t that enough? Well… maybe, but maybe not. The accreditation and approvals held by an institution and its programs affect what you can do with your aromatherapy training, including whether you can use that credential on a resume, gain insurance, or qualify for industry approvals or registration examinations.

Learn more about the value of attending an accredited aromatherapy program and ACHS’s accreditation with DEAC in this FAQ here.

Our Chief Strategy Officer Erika Yigzaw also wrote an excellent blog post on the value of accreditation and the pitfalls you might face at an unaccredited school.

As you learn more about the aromatherapy industry, it’s time to decide what level of aromatherapy program is right for your professional goals. Should you start with a single course? Maybe a certificate program? Or, maybe you’re ready for a master’s level education. Here is a brief breakdown of each program according to individual goals.

If you’re new to the aroma community, pursuing a quality aromatherapy education is a logical place to start.

You can take one introductory course in aromatherapy or you can jump right into a Certificate in Aromatherapy or a Diploma in Aromatherapy and become a Master Aromatherapist.

Taking a college class in aromatherapy will help connect you with peers who are at the same stage as you. Many students develop lifelong friendships and continue to support each other as they grow in the industry. Plus, you’ll get front row access to an experienced aromatherapy expert (your professor), who can offer professional guidance and mentorship. Another simple way to get involved with the aromatherapy community is by connecting with important industry organizations.

Here is a list of our favorite organizations doing remarkable things for the aromatherapy industry:

National Association for Holistic Aromatherapy Logo
National Association for Holistic Aromatherapy (NAHA)

NAHA is a nonprofit association “devoted to the holistic integration and education of aromatherapy into a wide range of complementary healthcare practices including self-care and home pharmacy.” NAHA also works hard to increase public awareness and knowledge surrounding essential oils and the safe and effective practice of aromatherapy in everyday life. NAHA hosts educational webinars and a biennial conference, the World of Aromatherapy Conference. You can also network by connecting with NAHA on social media. Follow on Twitter or Facebook.

Alliance of International Aromatherapists Logo
Alliance of International Aromatherapists (AIA)

AIA is a nonprofit organization with the aim to “increase awareness of and expand access to aromatherapists, help its members build successful practices, expand the body of aromatherapy research, and serve as a resource for members, the media, and the public.” The AIA seeks to make aromatherapy a more readily accessible, accepted, and respected holistic modality. Like NAHA, the AIA hosts educational webinars and a biennial conference(alternating years). Connect with AIA on Facebook.

United Plant Savers Logo
United Plant Savers (UpS)

The United Plant Savers are on a mission to “protect native medicinal plants of the United States and Canada and their native habitat while ensuring an abundant renewable supply of medicinal plants for generations to come.” UpS is comprised of herbalists, aromatherapists, and other plant lovers who want to support the ethical and sustainable growth and harvest of medicinal plants.

Connect with UpS on Facebook.

natural products association logo 2020
Natural Products Association (NPA)

The NPA is “the nation’s largest and oldest nonprofit organization dedicated to the natural products industry. NPA represents over 1,400 members accounting for more than 10,000 retail, manufacturing, wholesale, and distribution locations of natural products, including foods, dietary supplements, and health/beauty aids.” If you want to influence policies that affect how essential oils, herbs, and other natural products are made, marketed, and sold in the U.S., the NPA could be a great fit.

One way to ensure you’re recognized as an expert in your practice is by earning the Registered Aromatherapist (RA™) credential.

A Registered Aromatherapist has successfully demonstrated a core body of knowledge by passing the Aromatherapy Registration Council’s (ARC) Examination. The ARC Examination’s primary focus is the safe administration of essential oils and covers topics such as scientific principles, administration, and professional issues in aromatherapy. It is also available in a number of languages, including English, Japanese, Korean, and Chinese.

Once you have successfully passed the ARC Examination, you are added to their online international database of ARC Registered Aromatherapists. The RA designation (valid for five years) confirms your high standard of education and demonstrates a commitment to the ethical and safe use of essential oils with the public.

An additional perk: the ARC will also verify your registration status at the request of employers, government agencies, and anyone who needs to verify your professional qualifications. 

Here’s a step-by-step tutorial on how to become a Registered Aromatherapist (RA).

Here are several free and premium resources to expand your aromatherapy knowledge even further:

Aromatherapy eBooks

Essentials of Essential Oil Safety

Aromatherapy Everyday Basics

Top 10 Culinary Essential Oils

Green Spring Cleaning with Essential Oils

A Rose By Any Other Name…

Holiday Gifts to Make at Home

White Papers on the Aromatherapy Industry

Careers in Aromatherapy by Dorene Petersen

U.S. Trends in Aromatherapy Essential Oils by Dorene Petersen

Top Blog Posts

Green Cleaning: 10 Essential Oils that Naturally Repel Insects

Anxious or Feeling Down: Can Essential Oils Help?

Blending 101: The Art of Pairing Essential Oils Drop by Drop

5 Essential Oils for Men

Essential Oils and Head Lice

Debunking Dangerous Myths About Essential Oils

Top 5 Ways to Check Quality of Essential Oils

Top Videos

Making Natural Body Oil with Dorene Petersen

Lavender Distillation Demonstration

Rosemary Harvest for Distillation 

How to Correctly Store Essential Oils for Optimal Therapeutic Quality

On-Demand CE Courses in Aromatherapy

Basic Blending with Essential Oils, Presented by ACHS Aromatherapy Program Chair Amanda Lattin

Everything Organic: Essential Oil Production, Best Practices, Presented by Dorene Petersen

Boost Your Aromatherapy Practice: Intake & Case Study Strategies, Presented by Amanda Lattin

Introduction to Aromatherapy Formula Preparations, Presented by Amanda Lattin

The Ultimate Essentials of Essential Oil Safety, Presented by Dorene Petersen

ACHS Accredited Online Aromatherapy Programs

Certificate in Aromatherapy

Diploma in Aromatherapy Master Aromatherapist

Graduate Certificate in Aromatherapy

Master of Science in Aromatherapy

Frequently Asked Questions

Aromatherapy Programs

Foundational Understanding

This program is an excellent program to start out and get your feet wet. We recommend this program to students who want to gain a foundational understanding of the aromatherapy modality. This is an ideal program for someone who just wants to grow in their holistic health knowledge or a budding professional who wants to add an exciting credential to their resume. We also recommend this program if a student already has an associate’s degree and isn’t necessarily ready to move into a bachelor’s program.

Learn More About the Certificate in Aromatherapy

An In-Depth Study

We recommend this program for students who have very clear goals in sitting for the Registered Aromatherapist (RA) Exam (see more info below) as it meets the core requirements. The Diploma in Aromatherapy is ideal for students who want to jump into the field of professional aromatherapy but aren’t necessarily ready for a degree program.

Learn More About The Diploma in Aromatherapy Master Aromatherapist


Level Up Your Professional Career

We recommend this program to students who already have a bachelor’s degree and want to understand the deeper fundamentals of aromatherapy. This program is ideal for healthcare professionals—like nurses, doctors, psychologists, chiropractors, herbalists—who want to integrate aromatherapy in order to obtain a more well-rounded practice.

Learn More About the Graduate Certificate in Aromatherapy

Become a Leading Expert in Aromatherapy

The only accredited master of aromatherapy degree in the United States, we recommend this program to students who are excited to jump into professional aromatherapy, already have a bachelor’s degree, and want to sit for the RA exam. This is ideal for future clinical practitioners who intend to conduct scientific research, teach at a university level, become an aromatherapy product formulator, and more.

Learn More About the Master of Science in Aromatherapy

Your Passion Can Be Your Profession

Industry Leaders

ACHS Partnerships & Affiliations