I’d call the vet just to have peace of mind.

What are the details here? How many seeds? Do you think they were ingested? What type of behavior (odd) do you mean?

Call the National Animal Poison Control Center. You’ll find the number at this website.

http://www.aspca.org/site/PageServer?pagename=pro_apcc&JServSessionIdr001=rd6is4fca2.app25b

I find multiple references online to “wild radish seeds” being a toxin, but I’m not sure about the domesticated version.

The seeds contain thiocyanates, the same compound that gives horseradish its burn. It’s probably irritating your cats mucous membranes, which would explain the strange behavior.

Thiocyanates are toxic taken in significant quantities. They can cause inhibition of iodine uptake by the thyroid, which leads to hormone problems.

There is not an enormous amount of thiocyanate in radish seeds. They’re quite safe for human consumption.