I can say definitively that YES, smoking cannabis does lower blood pressure, but it does initially go up. I have anxiety driven hypertension, and have tried every pharmaceutical on the market. Some work somewhat, some not at all. My fiance' suggested I try small amounts of cannabis, and document my blood pressure at 30 minute intervals. So - I did exactly that on a weekend. I took NO blood pressure meds that day. I didn't want to muddy the test, but I had them on hand just incase it got too high. My initial BP was 160/107 at 6pm. Took 1 good hit at 6:05. At 6:30 it was 171/112 - entering scary territory. At 7:00 it was 174/111. Still too high and I was getting nervous. 6:30 (T+1:25) my BP was 155/98! It was coming down - and remember, I took no other BP meds at all. 7:00 I felt quite relaxed and had nice mellow buzz, and my BP was 131/82! Woohoo! Success!!! At 7:30 it was 128/80, and at 8:00 124/81. At this point, I was convinced. It remained in the 120's/80's all night and even into the next morning. And in the spirit of scientific experimentation, I repeated the experiment the next evening with nearly identical results. And... just to be absolutely sure, I did it a third time one week later, and had almost identical results! *Note: the stuff I had was some good indica hydro, and I only had 1 hit (about the size of a pea) each time. But the answer to the question of "Does cannabis lower blood pressure?" is a definite YES - although it will initially raise BP and heart rate for about an hour, BP will lower substantially (30-40 points both systolic and diastolic in my case). I hope that helps your question somewhat.