While it's true that any substance can be harmful if abused or used irresponsibly, the effects of marijuana are generally considered to be less severe than those of alcohol.
If you're interested in learning more about the potential benefits and risks of using cannabis for wellness and healing, as well as tips for safe and responsible use, you might want to check out mindbodygreen.com. They have some great resources on all sorts of wellness topics, including cannabis and plant-based medicine.