★★★★★
Pure MSM;
Nutribiotic's liquid GrapeFruit Seed Extract (liquid, 33% GFSE + 67% glycerin {essential buffer)
Oregano Oil
About 20 yrs ago I found these remedies on a dog-breeder's website after one of my dogs proved positive for it after having lost 10 lbs (went form 70 to 60 lbs).
She would NOT swallow ANYTHING containing the pills prescribed by conv. vet., so I looked online. Read an article saying that drug is not very affective for Giardia, & that it's Very Bitter! Then found the article sharing natural treatments....
I used the top 3 I listed, as I already had them. The 4th is one my sister later told me she uses for her dogs after they go hiking & swim in a place where they always pick Giardia up. I recall each of them was recommended as effective alone ... but I had 3 n hand, & they're all safe to use, so gave all of them to both my dogs (both showed symptoms I now recognized) mixed in their food w/ water....
PLUS, I gave the one diagnosed an extra feeding daily for a week (along with the nat. meds.), & she gained all her lost weight back that week, & did NOT loose weight after I stopped treating the Giardia!