OASIS VITA-DROPS Pure C can be added to the food or the drinking water, whichever is more appropriate and accepted by the guinea pig. The preferred method of using OASIS VITA-DROPS Pure C is to add the concentrated liquid supplement to the guinea pig's daily drinking water (whenever possible, use a sanitary water bottle instead of an open water dish, which can be easily contaminated with debris). Guinea pigs readily drink this mixture, but if desired the vitamins may be applied directly to their food.