Abnormal vomiting after cat deworming may be caused by excessive dosage of medication, or may be caused by a large number of parasites in the cat’s body. First, confirm whether the dosage of medication is correct. If If there is an overdose, it is best to go to the pet hospital immediately; if there is no overdose, you can observe the cat's condition. If it is not vomiting, it is fine. If it still vomits, it needs to be sent to the hospital for examination and treatment.