I urge caution in adding soy-based products too quickly (“Alternative meds update,” April 2010). After consuming only small amounts of soymilk with cereal, I developed angioedema and thickening of skin, which resolved after several weeks. Months later, the same symptoms recurred. After carefully reviewing my dietary intake, I discovered that soybean oil is a common ingredient in salad dressings.—Patricia Shay, ANP-C, Syracuse, N.Y. (140-16).