Is it safe to take ambient and benadryl (diphenhydramine) tigether?

Check with doc: Both cause sleepiness so combined makes even more so. Both can hurt you if you take too much, alone or together. It also depends on what other meds, drugs/alcohol, caffeine, you're taking & why you need the med in the first place. Good sleep is often obtained through good habits, and enough daily exercise & proper diet, to ensure a sound sleep. I bet a lot of marathon runners were ex-insomniacs!