What do you suggest if my friend drunk a bottel cap of toilet cleaning phenoyl if it will dangerous please tell me about its effets?

Probably too late: to do anything about it. Asking on Healthtap is not what I would advise in an emergency = there are poison control center hotlines in every city. If this friend drank phenol, even a bottlecap full may be highly toxic and s/he needs to go to the nearest emergency department, preferably in a Trauma Center if that is available. Since it is caustic, and may be combined with acids it needs expert care