 The reason I make my pesto with walnuts, instead of the more traditional pine nuts, is not only because walnuts are probably healthier. We're talking 20 times more polyphenols, but also because of a mysterious phenomenon known as PMS. Nope, not that PMS. Pine mouth syndrome, characterized by what has become my favorite word of the week, cacodusia, meaning a bad taste in your mouth. You can get it from heavy metal toxicity, seafood toxins, certain nutritional and neurological disorders, or from eating the wrong kind of pine nuts, termed pine mouth by the public. A few days after eating pine nuts, you get this persistent metallic or bitter taste in your mouth that can last for weeks. Thousands of cases have been reported. Raw versus cooked pine nuts doesn't seem to matter. Should the cause be some unidentified toxin present in some varieties of non-edible pine nuts? Out of more than 100 different kinds of pine trees, the nuts of only about 30 are considered to be edible. So pine nut samples from stricken consumers were analyzed, and indeed they all contained nuts from Chinese white pine, which is not reported to be edible. That tree is typically only used for lumber. These are the good ones. These are the bad ones. It's like a game—good, bad, good, good. You don't know it's the Chinese white pine nuts, though until you put it to the test. Researchers had a few folks consume 6 to 8 Chinese white pine nuts. Most of the subjects hadn't ever heard of pine mouth syndrome, and boom, they all developed symptoms. We still don't know exactly what it is in those nuts that causes such a weird reaction. We just know to stay away from those kind of pine nuts. So what kinds of pine nuts do we have on our shelves here? All kinds, apparently, including those associated with pine mouth. Good, good, good, bad, good. So unsurprisingly, hundreds of cases have been reported in the US as well. Most of the implicated nuts were reportedly labeled as originating from Asia, and in most cases, China. China actually did something about it and demanded China stop sending them toxic nuts, which they did in 2011. And this export restriction likely resulted in less being imported into the US as well, given the decline in cases going to 2012. Rare cases still happen, though, as evidenced by an active Facebook group entitled Damn You Pine Nuts. The primary reason I made this video is just to allay fear should this ever happen to you. Although there are no proven therapies, pine mouth syndrome appears to be benign and just goes away on its own.