"Papaya Tablets - These enzymes may help soften food and hair in the stomach. The best prevention for hairballs is an ample consumption of fibre in the diet, provided by large quantities of grass hay. Always make sure your rabbit is drinking plenty of water, as water consumption plays a big part in maintaining digestive motility thus improving the health and efficiency of the digestive system. Offer 1-2 tablets daily. You may increase the dosage to 3 tablets during moulting or for long haired breeds."
So - hay and water are the best options but if in doubt give your bun 3 tablets? :?