Can a Chihuahua eat pasta?
Cooked, yes, with no sauce.
How much: A teaspoon of plain boiled pasta, no sauce or salt, very occasionally.
Why
Cooked pasta is harmless but offers very little nutrition. Sauces with onion, garlic or concentrated tomato are off-limits.
Pasta 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.