Things that are good to drink when you have diarrhea are fruit juices, water, orange juice, chicken broth and tea with honey.
Another good thing to have on hand and drink when you have diarrhea is Pedialyte which helps to replace lost electrolytes.
Pedialyte is also good for adults and not just children so if you're having diarrhea drink at least some Pedialyte to help keep your electrolytes up along with drinking the water, tea, Juice etc.