I changed my mind again about grapefruit seed extract. Today I was feeling horrible and having a nasty nasal drip. I have been using oregano oil and clove oil together with the rest of my regimen and still having this problem. I put 10 drops of Citricidal grapefruit seed extract(that is 100 mg, a standard dose) in a cup of water. That gave me quite a bit of relief. I also read about the toxicity of oregano oil in larger doses and decided to cut back on the oregano oil to 3 drops(mine is 1/3 diluted. For pure oil, use just one drop) just 3 or 4 times a day. I may add lemon oil and peppermint oil to my regimen soon. I read that lemon oil(and I guess this is true for other fruit oils?) needs to be refrigerated after opening it.