If a person who has never been seasick suddenly becomes seasick after riding in a car, it is likely that he or she did not rest well before riding in the car, had insomnia at night or ate particularly greasy food before riding in the car, because the ride may be bumpy and will stimulate the food inside the stomach to roll back and forth, which is particularly likely to stimulate nausea and vomiting. Patients may not exercise at all, and their physical quality may decline, and they may suddenly become seasick, looking out of the window or playing with their cell phones while riding in the car, thus inducing vertigo. It is advisable to be prepared before riding in a car to avoid motion sickness. If motion sickness is particularly obvious, you can take Benadryl tablets orally.