Add them gradually, @Outlier. Start small amounts and increase over a couple of weeks, to allow your digestive system to get used to them. I also use milled flax seeds.
I use them to make sure the fats I am consuming are adequate. Not being able to cope with too much butter, cream, cheese and fatty meats.
Chia seeds swell up quite a bit when added to liquid. I made the error of having a large spoonful dry sprinkled on some yogurt. Some stuck in my throat and they clinged making me gag. I let them soak for a few hours now, before eating. They are great on berries, to make jam. Also to thicken soups.