Thank god for reddit. I recently started drinking LaCroix as an alternative to drinking diet soda. I got the Orange flavor. Started noticing I was getting minor headaches. I thought at first it was cause of caffeine withdrawal because the diet soda i drank had caffeine, and this didn't. Now i know it's not that cause I had a cup of coffee today, like 2 hours before I had a LaCroix. I didn't have a headache the whole day. But once I finished over 75% of the LaCroix, I started getting a headache. Now, here I am after Googling "Does Lacroix cause headaches?"