According to The University of Utah (http://poisoncontrol.utah.edu/plants/plantGuide/fireThorn/fireThorn.html), Firethorn (Pyracantha species) toxicity includes possible skin and stomach irritant. You can also google and find alternative relevant potential research based materials including http://mason.gmu.edu/~mtadayon/firethorn.html, which details the toxicity and symptoms of Firethorn as … a poisonous plant. The berries are the most toxic part, and could cause vomiting, stomach ache, blistering of tongue and diarrhea upon ingestion. The sap of the plant could also cause skin rash and irritation. Upon contact, one should immediately wash the affected area with water and soap and in either case (ingestion or irritation) call his/her doctor. Firethorn belongs to a genus where most, if not all the members produce the toxic poison hydrogen cyanide (HCN), which is what gives the berries their bitter taste. It is also the ingredient that causes skin irritations and is found mostly in the berries and the leaves. Ingestion of HCN can be fatal, however, since its concentration relatively low in the plant, it may only cause minor illness, as mentioned above. Another Toxin present in Firethorn is called maytansine, which is believed to be produced by microorganisms associated with the roots of the plant rather than the plant itself. Extracts of pyracantha also contain chloroform, acetic ether and petroleum ether, which can be toxic at high concentrations.

I would say to stay away from this plant if there are concerns:)