If necessary you can take Loperamide 2mg capsules up to 8 in 24hours for diarrhoea
Once the bowel is upset, it then has problems digesting milk. Avoid milk products for 24-48 hours Drink plenty of water or rehydration solutionEat small bland meals Eat fresh boiled rice as this slows down gastric transit
Cramping can be helped by dimethicone or peppermint oil capsules. Peppermint tea is really good to help settle the digestive tract.
Ensure you keep fluid levels up. If you do all the above, it should settle down in 24 - 48 hours however if you have been abroad recently, or there is blood, mucus or pus in the stool, then see your doctor. Any severe pain or temperature should also be reason to contact the doctor sooner.