In many states across the Nation there are approved marijuana growing facilities that are strictly monitored by government agencies.
These sites can be for medical or recreational use but the main thing is, they are regulated to ensure that the plants are grown properly.
In many ways, whether you agree with its use or not, this can make the substance safer for the consumer. When this controlled substance is grown by the average person without regard to any of these guidelines it can be altered by pesticides and other chemicals. The plant can contain trace amounts of these and then they are introduced into the user. This is especially important if a person is using the marijuana for medical purposes. They may live in a state that has not approved its use for their condition and they turn to a street dealer to get the product. There is no way to know how this substance was grown or under what conditions. If there are any trace additives they may adversely affect the person and their medical condition may worsen. It is important to get a quality product from a reputable company whenever possible. Even if you are forced to order that product from out of state you are better off than taking chances with some guy on the streets. So long as you have a prescription that is written by a certified physician you can order your medical marijuana from a certified distributor. If you are looking to purchase the product for recreational use you would need to be in a state where its use as been approved for that.