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Revisiting this topic with an update which may be of interest. My wife in conversation with a pharmacist about this attack mentioned that one thing we had both eaten was quite a lot of melon on the previous day, she (the pharmacist) told her that it was a known fact that melon could produce such fierce attacks like this, checking further I find it's because watermelon contains large amounts of water, and is high in fructose which is digested by the liver and this puts a lot of strain on it. If your liver can't handle the amount of fructose it is getting, then you will end up with too much digestive juice in your digestive system. The extra liquid will push out whatever is in your system "like a garden hose" - a pretty good description!
Has anyone experienced this, and is Sqad around to comment please?