Hi Suzi - I don't know if this would apply but thought I would mention it just in case. Early in the radiation treatment, my son had a bad reaction to some anti-nausea medication where he couldn't breathe and his tongue swelled up to the point where he had to make a trip to the emergency room where they gave him two shots of Benadry which was in the same dosage as is available over the counter. The doctors told him he could take Benadryl at home if he had any more problem, but he was also switched to a different anti nausea medicine. This may not be the same thing as what your Mom is experiencing and you should of course check with the doctor before trying anything new to make sure it's ok with whatever other meds she is taking.