When you buy marijuana, you may not know exactly what's in it. Most states require marijuana products to be tested for potency and the presence of pesticides and molds, but there are still a number of other things that can be found in weed, including:

- Heavy metals: Marijuana plants can absorb heavy metals from the soil they are grown in, such as lead, mercury, and arsenic.

- Pesticides: Marijuana plants can be treated with pesticides to kill insects and other pests, and some of these pesticides can remain on the plant after it has been harvested.

- Mold: Marijuana plants can be contaminated with mold if they are not properly dried and cured. Mold can produce toxins that can cause health problems if inhaled.

- Bacteria: Marijuana plants can also be contaminated with bacteria, such as E. coli and salmonella. These bacteria can cause food poisoning if ingested.

- Other plant materials: Marijuana may also contain other plant materials, such as twigs, leaves, and seeds. These materials can make the marijuana less potent and may also be irritating to the lungs if inhaled.

In addition, marijuana may also contain other substances that have been added intentionally, such as:

- Synthetic cannabinoids: Synthetic cannabinoids are man-made chemicals that mimic the effects of THC, the active ingredient in marijuana. These chemicals can be more potent than THC and can cause a number of serious health problems, including anxiety, paranoia, seizures, and death.

- Adulterants: Adulterants are substances that are added to marijuana to increase its weight or potency. Some common adulterants include sugar, flour, and even rat poison.

It is important to be aware of the potential risks associated with marijuana use. If you are concerned about what may be in your weed, you should talk to your doctor or a qualified healthcare provider.