You asked about this in your previous thread (Bone marrow transplantation (currently 1month and 3 day)
There are a few aspects to consider. Getting in legal trouble is obviously one concern, which you already know. Does that prevent you from asking your doctor about using marijuana? Legal issues also prevent marijuana from being more extensively studied.
On the medical side, there are two questions you might ask: Are there medical benefits to using marijuana? What are the risks of using marijuana?
Here are some previous forum discussions related to these questions:
There is also information at other websites:
This question and answer
are about the use of THC (the chemical in marijuana) for the Epstein-Barr Virus.
There's a marijuana website with a discussion about marijuana after transplant
Patients taking an immunosuppressant like Tacrolimus (fujimycin) after a transplant have a risk of drug interactions if they use marijuana, as reported in a medical journal
An old study
found that transplant patients who subsequently used recreational marijuana had reduced life expectancy, while later research
supports the use of THC under a doctor's direction.
The Cleveland Clinic, a very well-respected medical center, weighs in with their advice
about avoiding infections after a bone marrow transplant:
Avoid tobacco and marijuana use. The use of these substances, along with exposure to environmental tobacco smoke (second-hand smoke), increases your risk for bacterial, viral, and fungal infections.
As you can tell, there's still a lot of debate and discussion about the risks versus benefits. If there's any chance that you can talk to your doctor about it, I recommend doing so.