You know when you go to the dentist and get Novocain? That is cocaine based. Same as Lidocaine. Opioids are based on the same drug as heroine. They have both have their place in proper medicine.
And as for being told marijuana is bad for you, it has always been one of those things that some misguided people used misinformation to make the laws. It has long been known to have good and bad properties. Native Americans knew about the medicinal properties. It actually grew as a weed in many parts of the US.
During the depression era law makers made marijuana illegal as a way of trying to oust or control Mexican immigrants. They thought by making it illegal they could easily deport them for breaking the law. That way our country that was strained fiscally could reduce the population and leave more economic resources for whites. That is when the movie Reefer Madness came out, to help turn the public opinion against it.
Since about the time I got out of high school, in 1980, I had started hearing about the medicinal advantages to marijuana. At that time the big one was using it to treat glaucoma. Then we started hearing about it helping people going through chemotherapy. Now it is used for treating seizures, anxiety, Parkinson's, Tourette's, migraines and multiple sclerosis.
Legalizing it for medical use will be on the ballot this fall in Florida. I will be voting yes.