I was very surprised to learn how much research has been done on this product. It appears that if you were ingest a very large quantity, it "might" be harmful. That said, I am not a Doctor or a research scientist... Apparently there are 2 grades, one used as a food product in items such as bubblegum; while the other is used in things like floor wax. Below are a few paragraphs from my research which should answer your question. I have also added the links I used. Hope this helps. The present Committee reviewed new studies with 14C-labeled glycerol ester of wood rosin administered to rats and in vitro, which indicate that the food-grade material is quite stable in the gastrointestinal tract and that only a minor fraction, most likely the monoglycerol ester fraction, undergoes partial enydrolysis. The Committee therefore based the present evaluation on the new studies showing the metabolic stability of glycerol ester of wood rosin and the toxicological data available for food-grade and non-food-grade material and wood rosin evaluated at the forty-fourth meeting (Annex 1, reference 116). From these studies, it was concluded that glycerol ester of wood rosin has no genotoxic properties; wood rosin at doses up to 434 mg/kg of body weight (bw) per day did not induce any treatment-related histopathological changes in a long-term study of toxicity and carcinogenicity in Sprague-Dawley rats; and the food- grade material was less toxic than the non-food-grade material in 13-week studies of toxicity. 4. EVALUATION Although there were no long-term studies of toxicity or reproductive toxicity available, the Committee considered that the data from previously reviewed studies and the new studies confirming non-bioavailability were adequate to establish an ADI. Therefore, on the basis of the 13-week toxicity study in rats with food-grade material, in which the effect level was 2500 mg/kg bw per day, the Committee allocated an ADI of 0-25 mg/kg bw, applying a safety factor of 100. The Committee did not round the ADI to one significant figure, because such rounding would have resulted in a decrease in the value of the ADI of 20%. http://www.inchem.org/documents/jecfa/jecmono/v37je02.htm 2.2.1 Acute toxicity studies The results of acute toxicity studies with wood rosin are summarized in Table 1. Table 1 available at: http://www.inchem.org/documents/jecfa/jecmono/v35je05.htm