Environmental factors aside, what makes one strain of marijuana produce a different high to another? What is in one plant that isn't in the other? I always thought THC was the active ingredient. Consume THC, you get high, simple as that. But if it's simply this one chemical that produces the high, then what else, in the bud, effects different characteristics of the high? Is the THC in one bud different to the THC in another bud? Are there other chemicals besides THC that effect the high? Reading through the grow guide here on Marijuana.com, I see that apparently there are actually other chemicals that can effect the high: " When Cannabis buds are picked in a more mature state, the levels of THC drop and the levels of CBN and CBD increase. This fluctuation is cause for a more 'down' and stoney high." What are CBD and CBN? I've never heard of these before? What other chemicals should I know about? I have felt the different characteristics of the high of one strain compared to another, in as much as regularly smoking the bud of an unknown strain for a period (say three weeks), and then buying another amount of weed, and smoking that regularly for a period. I feel certain characterstics of the high which are specific and consistent to one lot of weed, and a different set of characterstics for the other. But what exactly causes this? And once again, I am not talking about environmental factors, like when and where the weed is smoked. People talk about factors like where it is grown, how it is cured, hydro or outdoor. But I thought that really, these factors only effect superficial characterstics, like how smoothly the bud smokes (dried properly), or the concentration of THC (Hydro vs outdoor, or drying properly again). I can see how hydro can have stronger concentrations of THC (meaning smoke less, get the same high - or smoke same amount, get higher than you expected), but how can it change the high? What changes the high?