THC is lipid and alcohol soluable. This means that if you put weed in fat or alcohol, the THC will be absorbed by the solvent. If you were to just eat the weed straight, you wouldn't get very high because your stomach does not have the correct solvents to extract the THC with. If you eat enough you might get buzzed, but if you want to ingest THC you have to do it through a lipid or alcohol medium (e.g. brownies, space cakes, firecrackers, green dragon, absinthc)