You will need an anti-microbial herb product to kill giarida. I just did some research on the internet and found that Paraclear claims to kill the micro- parasites (i.e. flukes, amoebae, protozoa, giardia) in the human system. I looked at the ingredients and they are very similar to the ParaGONE that I am taking now.
You can buy the Paraclear here or pick up the ParaGONE at the healthfood store.