Robert DuPont is a respected authority on drug issues, but he also has strong anti-cannabis beliefs that apparently caused him to leave out important facts in his writing on medical cannabis ["Where there's smoke, there's a health concern," Local Opinions, April 25]. He stresses the dangers of smoke but doesn't mention that cannabis can be inhaled smoke-free by using a vaporizer. He says that dosages are uncertain, but legally regulated cannabis could be produced with a known THC content. Similarly, cigarette packs show tar and nicotine amounts. Finally, he ignores the fact that for conditions such as pain and nausea, the therapeutic dose can vary, so inhaling small increments of fast-acting vapor (or smoke) is a superb delivery system because it allows the patient to adjust the dose as needed.