Ulcers. These are sores that develop in the stomach or duodenal lining.

B.Mood-altering chemicals derived from plants.
please correct my answer if its wrong
Answer:
Potential dangers are that he is older and could take advantage of you when he is high (if he smokes pot). And if you are not comfortable dating someone then you should never date them. So the best thing to do in this situation is to probably tell the person how you feel.
I hope this is an okay answer
For the patient with head injury and increased Intracranial Pressure (ICP), an osmotic diuretic, such as mannitol, is very helpful. An osmotic diuretic works by creating an osmotic gradient in the blood by the presence of the additional osmolyte (mannitol). In other words, the osmolyte stays in the bloodstream and creates a greater osmotic force to pull water out of tissues and third spaces (interstitium of cerebrum). This aids in alleviating the addition ICP by fluid removal.
The extra fluid that was "sucked" into the bloodstream via osmosis, can then travel to the kidneys and be filtered out into the urine (diuresis). This explains its two purposes as an "osmotic" and a "diuretic."