Hello, Thank you for your query Hormonal methods of contraception can cause menstrual irregularities. The diarrhea of food poisoning is worse than that due to the hormones. However, food poisoning does let more than a day unless you also have an intestinal infection. *how frequent are the loose stools? *any vomiting? *where exactly does your abdomen hurt? Lower/upper part, left or right? Is the pain associated with a loose stomach or passing gas? I recommend : - wait for two days. - drink plenty of water. If diarrhea more than twice a day, have oral rehydration solution (Gatorade will do), about 200 ml after every loose stool. This is in addition to your regular water intake. -have a bland diet (avoid oily, spicy and fatty food) -have warm fluids, semisolid diet. -avoid milk and sugar. Use honey if necessary - once better, try Papaya, pineapple to induce a period. -take a probiotic every daynor yogurt with active cultures. If the diarrhea is more than 5 times a day, or your pain worsens, see your doctor right away. - blood tests (complete blood count) -stool analysis and culture -antibiotics may be needed If this recurs or is uncomfortable, you may want to consider another method of contraception. Symptoms may ease up on continued use of the pill. So you may want to consider that if symptoms are mild. Hope this helps. Please let me know if there is anything else I can help you with. Wish you good health