No hard proof that I am aware of. A chemical capable of destroying small life sometimes damages of large lifeforms it touches. Sometimes poison works that way (e.g. DEET)

Also, does tumeric really kill fleas? Are we just gonna take their word for that? I seriously doubt it.

[–] Deathray5@lemmynsfw.com 2 points 3 weeks ago

Spices do typically kill bugs. It's their entire purpose. Because they work by dehydration and larger animals with access to water can just drink more, it's also very safe

[–] MDCCCLV@lemmy.ca 2 points 3 weeks ago

A lot of insecticides are poisonous to animals including mammals it's just that we have a mechanism that deactivates or neutralizes it immediately. They often target a basic metabolic process that is common across all life.

[–] pinball_wizard@lemmy.zip 2 points 3 weeks ago

Is there any evidence for that?

Yes. Cats can go into seizures from popular flea medicines.

https://www.petcarerx.com/article/tick-and-flea-medicine-poisoning-in-cats/4602