Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it looks like dry mouth along with metallic taste at the back of throat can be due to causes like severe dehydration, side effects of medications if you take any, salivary gland dysfunction etc.. While diarrhea can also be due to electrolyte imbalances, stomach infection or gastroenteritis, food poisoning,side effects of medications etc.. Even excessive diarrhea can also cause excessive water loss from body and can further exaggerate dehydration and dry mouth.. You should consult a General Physician and get a proper evaluation done and a stool culture can help in confirmation of the cause of the diarrhea and treated accordingly.. As of now you should first of all start with replenishing fluids and electrolytes in body and drinking plenty of water and oral rehydration salts dissolved in water can help.. Take more of foods like cereals,bread,rice, probiotic like Yoghurt etc.. Take Loperamide to stop diarrhea. And once the cause of diarrhea will be ruled out treating the underlying cause will help in resolution like antibiotics if there is infection.. For dry mouth along with drinking water, chew sugarfree chewing gums.. If the dry mouth does not resolve even after diarrhea improves, consult an Oral Physician and get evaluated.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.