Can a Chihuahua eat chamomile?
Mild, cooled tea, yes.
How much: A teaspoon of cooled chamomile tea diluted in his water if he's nervous or has a mild tummy upset.
Why
It has a calming and anti-inflammatory effect. Helpful for a little digestive discomfort. Don't give him the whole plant: some dogs are allergic.
Chamomile in a Chihuahua's diet
Keep in mind how tiny the portions are for this breed: an adult Chihuahua eats roughly 1 to 2.3 ounces (25-65 g) of food a day depending on his weight, and treats shouldn't go over 10% of his daily calories. That's only a small fraction of an ounce. What looks like "a little bite" to us can be half a meal for him.
This information is for general guidance and is not a substitute for advice from a licensed veterinarian. Every Chihuahua can react differently; if in doubt, always check with a professional.