Petroleum-based laxatives and hairball remedies coat the swallowed hair and the stool and allow it to pass through the digestive system.  Use these products under the direction of a veterinarian since frequent long-term use could result in vitamin deficiencies.  Do NOT force feed, since the petrolatum could be aspirated into the lungs and cause serious side effects.  Overdose can result in diarrhea.  This product should be given in between meals to decrease chance of limiting fat-soluble vitamins from being absorbed.