The healthiest way to use medical cannabis is, in a word, vaporizing. This process has its roots in Ancient Egypt. Large flat stones were heated in fires until they were glowing hot before being carefully removed and sprinkled with different types of incense, including cannabis. As there was no burning process, the vapours laden with the pungent (and in the case of cannabis, psychoactive) oils and aromas which were released were far purer and more effective than if the ingredients were burned.
This principle still holds true today, though luckily there have been many technological advances in the design of vaporizers, and the days of having to heat stones in a wood fire to ingest medical cannabis are over. Sensi Seeds (sensiseeds.com) have a good range of different sized vaporizers, ranging from the highly portable, pocket sized Iolite and Da Vinci vaporizers to the Volcano and Verdamper vaporizers, which may need their own chair or table.