It should. Oleander works against all types of tumors and irregular cells. Make sure to increase the dosage slowly. Start with one, and then go up gradually. If at any time you get diarrhea or digestive upset wait until the symptoms have subsided before you increase the dosage again. It should only be a few days. Now......... The ultimate dosage for cancer is 8 capsules daily. I'm not really sure what the dosage for a benign tumor is, if its the same or maybe less. I am going to send you the manufacturer's email by private message so that you can ask him directly.