Marijuana (THC)

What is it?
First Aid

What is marijuana?

Marijuana is the dried leaves and flowers of the cannabis plant. It contains the drug THC  (tetrahydrocannabinol). Other preparations of the cannabis plant include hashish and hash oil.

Marijuana can be harmful to young children or pets who swallow it unknowingly. Children may be especially drawn to edible products, such as brownies, cookies and candy.

Is marijuana an illegal drug?

Marijuana is a controlled substance under federal law, making it illegal to possess. However, a number of states, including Maine, New Hampshire and Vermont, have passed laws allowing medicinal use of marijuana. Some states have passed laws allowing both medicinal and nonmedicinal use of marijuana.

Note: Synthetic marijuana products, such as K2 and Spice, are designed to mimic the effects of THC, but can be very different. Learn about these street drugs on our synthetic cannabinoids page.

What are the effects of marijuana?

Typical effects of marijuana and other cannabis preparations include:

  • Sleepiness
  • Dizziness
  • Decreased coordination
  • Slowed reaction time
  • Increased appetite
  • Dry mouth
  • Coughing and lung irritation (if smoked)
  • Euphoria (a high)

Using marijuana can make it unsafe to drive.

Long-term use of marijuana can sometimes lead to dependence or addiction. Use of marijuana can also make the symptoms of depression, anxiety or psychosis worse.

Marijuana poisoning symptoms

Children who accidentally swallow marijuana can become very drowsy and have trouble breathing. In severe cases you may not be able to wake the child up.

Teens and adults who use a large amount of marijuana, especially edible products, may throw up repeatedly, anywhere from several hours to a few days. This is a type of cyclic vomiting syndrome. They may also experience intense and unpleasant hallucinations.

Pets can have symptoms similar to those seen in people, including loss of coordination, slowed reaction time and drowsiness.

What should you do if someone has used marijuana?

  • If a child has swallowed marijuana, call the poison center at 1-800-222-1222 for immediate advice. A poison specialist will tell you what to do at home and whether you need to take the child to the hospital. In most cases, a child who has swallowed an edible marijuana will need to be watched at a hospital.
  • If a teen or adult has used marijuana and isn’t feeling well, call the poison center at 1-800-222-1222, chat online or text POISON to 85511.


What can you do to prevent marijuana poisonings?

Keep marijuana—especially edible products—up high, out of reach of children and pets, in a locked cabinet if possible.

If you or someone you know has a substance use problem, use SAMHSA’s treatment services locator to find help near you.

Last Updated: Monday May 16th 2016