Cat Has Worms - Help!

[Americano75]

So we've discovered that one of our cats has worms and I'm freaking out a bit and the vets are closed tomorrow. Realistically can this wait until Tuesday or do I trust over the counter on the spot treatment?

Thanks!

We signed up to the Pets At Home monthly delivery. Each month they send you a wormer and de-flea via the post. We bought the first one in store. Reminds me to do it every month when it arrives! No more worms or fleas!

I'm going to do that from now on!