If somone is allergic to all antihistamines, what else can they take for motion sickness?

Motion sickness: In many people nausea can be helped by acupuncture (best) or acupressure at mh6. (master of the heart 6) which is on the ventral forearm about 3 finger widths proximal to the crease between the forearm and the hands stimulate the areas bilaterally by mashing on a small dull thing like a bb. Also there are a number of other anti nausea medications your doctor can give you that are not antih.

Transderm Scop (scopolamine): You can try a scopolamine patch (rx only) which will last for 3 days. I have never heard of anyone allergic to all antihistamines although one may experience similar side effects such as drowsiness and dry mouth.