CBD is often sold with the visual language of wellness: soft colors, plants, sleep claims and phrases such as natural or non-intoxicating. None of those things makes CBD risk-free.
FDA data identify concerns involving the liver, medication interactions, drowsiness, and other side effects. This guide is a starting point, not a substitute for a pharmacist or clinician who can review your medications and health history.
CBD Can Affect More Than How You Feel
Liver
CBD can raise liver enzymes, and liver changes may occur before a person notices symptoms.
Medications
CBD can change how other drugs work, and other drugs can affect CBD exposure.
Alertness
Drowsiness and sedation can occur and may be stronger with alcohol or other sedating substances.
Pregnancy
The FDA strongly advises against CBD use during pregnancy and breastfeeding.
Commonly Reported CBD Side Effects
The FDA identifies several side effects that can occur with CBD, including:
- Changes in alertness, especially drowsiness or sleepiness
- Diarrhea or other gastrointestinal distress
- Decreased appetite
- Mood changes such as irritability or agitation
The current FDA prescribing information for Epidiolex, the approved prescription cannabidiol product, also documents adverse reactions such as somnolence, decreased appetite, diarrhea and liver-enzyme elevations in clinical trials.
CBD and Liver Injury: What FDA Research Found
The liver warning is not based only on very high prescription doses.
FDA Center for Drug Evaluation and Research investigators conducted a randomized, double-blind, placebo-controlled trial in healthy adults. Participants in the CBD group received 2.5 mg/kg twice daily, equal to about 250 to 550 mg of CBD per day, for 28 days.
Among participants receiving CBD, 5.6% developed ALT elevations above three times the upper limit of normal after four weeks. No participant in the placebo group met that threshold. The FDA also reported that 4.9% of CBD participants met withdrawal criteria for potential drug-induced liver injury.
The participants with enzyme elevations did not experience clinical symptoms related to liver function during the study, and the enzymes returned to normal after CBD was discontinued.
What That Study Does and Does Not Tell You
- It shows that measurable liver changes can occur in healthy adults using CBD without other medications.
- It shows that liver injury signals can be silent rather than obvious from symptoms.
- It does not establish the risk at every lower retail dose.
- It does not provide a personal “safe dose.”
- It studied a controlled CBD oral solution, not every formulation sold online or in stores.
CBD Can Interact With Medications
The FDA warns that CBD can affect how other drugs work, potentially increasing side effects or reducing a medication’s effectiveness. Other drugs can also change CBD exposure.
That is not a niche issue. The 2026 Epidiolex prescribing information documents several clinically relevant interaction pathways and gives medication-management instructions for certain drugs.
Medication Situations That Deserve a Pharmacist or Clinician Review
- You take one or more prescription medicines every day
- You take medicine that can cause drowsiness or sedation
- You take seizure medication
- You take a medicine known to affect the liver
- You take a medication with a narrow therapeutic range
- You use several supplements or herbal products in addition to medications
- You are considering CBD because of symptoms caused by an existing medication
Do not stop, reduce or increase a prescription medication because of something you read about CBD online. Bring the CBD product label and medication list to the pharmacist or clinician who is reviewing the combination.
CBD, Alcohol, and Other Sedating Substances
The FDA warns that combining CBD with alcohol or other drugs that slow brain activity can increase sedation and drowsiness. The current Epidiolex label likewise warns that other central nervous system depressants, including alcohol, may increase somnolence and sedation.
If a CBD product makes you unusually sleepy, dizzy or mentally slowed, do not drive or operate hazardous machinery while affected.
CBD During Pregnancy and Breastfeeding
The FDA strongly advises against using CBD, THC or marijuana during pregnancy or while breastfeeding.
The agency states that comprehensive research on CBD’s effects on a developing fetus, pregnant person or breastfed baby is lacking, while existing evidence gives reason for concern. FDA also notes the possibility of THC and other contaminants in CBD products.
If you are pregnant, trying to become pregnant or breastfeeding, do not treat a retail CBD label as reassurance of safety. Discuss symptoms and treatment options with a qualified healthcare professional.
What If You Already Have Liver Disease?
Prescription cannabidiol labeling requires dose adjustments for moderate or severe hepatic impairment and monitoring of liver tests because of hepatic-injury risk.
A consumer CBD label does not provide the medical monitoring built into an approved prescription-drug program. If you have liver disease, abnormal liver tests or take medications that can affect the liver, CBD use deserves clinician review rather than self-directed dose experimentation.
Does Topical CBD Have the Same Interaction Risk?
The answer is not established well enough to make a blanket promise. The FDA notes important unanswered questions about how different routes of CBD use, including oral use, smoking, vaping and topical application, affect exposure and risk.
Do not assume “topical” automatically means no systemic exposure or no interaction potential for every formulation. Product design, skin condition, ingredients and how the product is used can differ.
CBD Side Effects Can Be Confused With THC Exposure
CBD can cause drowsiness and changes in alertness. THC can produce intoxicating effects. A consumer who feels “high” after using something sold as CBD may need to consider both the effects of CBD and the possibility that the product contains THC or another cannabinoid.
When a CBD Reaction Deserves Medical Attention
Seek prompt medical care for severe, worsening or dangerous symptoms. Examples include trouble breathing, loss of consciousness, seizure, severe confusion, repeated vomiting, signs of a serious allergic reaction, or symptoms suggesting a serious liver problem such as jaundice or very dark urine.
For less urgent but persistent symptoms, a pharmacist or clinician can help separate possible CBD effects from medication interactions, THC exposure and other causes.
Five Questions to Take to a Pharmacist
- Could CBD change the level or effect of any medicine I already take?
- Could any of my medicines increase CBD exposure or side effects?
- Do any of my medications already cause drowsiness?
- Do I take anything that already carries a liver warning?
- Are there symptoms or laboratory tests I should discuss with my clinician?
Bring the exact product label if possible. “I take CBD” gives a pharmacist less information than the formulation, milligrams, other cannabinoids and ingredient list.
What the Label and COA Can Contribute to a Safety Review
| Evidence | Why it matters |
|---|---|
| Total labeled CBD | Provides a starting point for discussing exposure |
| CBD per serving | Shows how the manufacturer divides the package |
| Other active ingredients | Helps identify sedating botanicals, melatonin, caffeine or other compounds |
| THC and THCA results | Helps distinguish CBD-only safety questions from possible THC exposure |
| Batch match | Shows whether the laboratory evidence belongs to the product in hand |
| Contaminant panels | Shows what safety testing was and was not performed |
Frequently Asked Questions
What Are the Most Common CBD Side Effects?
FDA materials identify drowsiness or sleepiness, gastrointestinal distress such as diarrhea, decreased appetite and mood changes among known CBD side effects.
Can CBD Damage the Liver?
CBD can cause liver-enzyme elevations and liver injury is a recognized safety concern. Newer FDA research found liver-enzyme elevations in some healthy adults taking 250 to 550 mg per day for 28 days. That finding does not define the risk at every lower dose.
Does CBD Interact With Prescription Medication?
It can. FDA guidance and prescription cannabidiol labeling document drug-interaction risks. A pharmacist or clinician should review your actual medication list.
Can I Drink Alcohol With CBD?
Combining CBD with alcohol may increase sedation and drowsiness. Avoid driving or hazardous activity while affected.
Is CBD Safe During Pregnancy?
The FDA strongly advises against CBD use during pregnancy and breastfeeding.
Is a Lower CBD Dose Automatically Safe?
No universal threshold has been established that makes every retail CBD product safe for every person. Risk can depend on the person, medications, product composition, route and exposure.
Primary Sources
- U.S. Food and Drug Administration: Consumer Update on CBD
- FDA CDER: CBD Safety in a Randomized Trial
- FDA: Epidiolex Prescribing Information, revised May 2026
- U.S. Food and Drug Administration: CBD During Pregnancy and Breastfeeding
- Centers for Disease Control and Prevention: About CBD
Last checked: September 3, 2026. Prepared by CBD Cafe Editor from the linked public records. General educational information only. Do not change prescription medications or medical treatment based on this page. This page has not been individually reviewed by a physician, pharmacist, hepatologist, or toxicologist.