Why would apple cider vinegar give me an instant headache?

Headache Trigger: May i ask how much apple cider are you consuming. Headaches have many triggers including specific smell, taste, stress, lack of sleep etc. The good thing is that you have identified what gives you a headache. So, definitely do not sign up for a job at an apple orchard. But how experimenting with other drinks (my favorite: unsweetened ice tea), that might keep you cool all summer.

Headache cure: If your instant headache happened every time when you take apple cider vinegar and pain went away in few minutes, then you should check with dentist see if there is problem with your teeth. If the symptom last and does not go away by itself, you should consult with your physician for further evaluation.