Short term memory loss, it can also be mentally addictive but cig's and alcohol is proberly more addictive anyway (cigs are phyically addictive). Its one of the safest drugs known to man. It could also make you put on some weight if u get the munchies alot. Thats about it really, oh yea, and the smoke proberly is'nt good for your lungs but you can digest marijuana anyway, but that just takes a whole lot more weed, and you can also buy a vap.