I did a search on chia pet and found the plant is supposed to be a kind of sage. According to the lists of plants poisonous to cats, sage is not listed. But I am always ultra careful with plants around cats.
Someone else may know for sure.
See I used to have a Chia pet and always thought they were like bean sprout type things... so I got curious
from the FAQ on the Chia pet website:
What are Chia seeds? "Chia" is the common name for salvia columbariae, a member of the watercress family.
Are Chia sprouts edible? Joseph Enterprises has never sought FDA approval for Chia Pets and Chia Heads, and therefore cannot promote them as a food product. Chia seeds are sold in health food stores, however, and many organic gardens harvest them for salads and sandwiches. Joseph Enterprises' Chia seeds are not treated with any chemicals or fertilizers.
My cat ate the sprouts. Is this a problem? No. Many cats eat greens when they have an upset stomach, in order to induce vomiting. Keep in mind that your cat may be eating the Chia sprouts because it already ingested something poisonous, and wants to throw up. Or it might just like to nibble on grassy stuff. Use your judgment, and when in doubt, call a veterinarian.