foamと聞くと、洗顔フォームのfoamを想起する方もいらっしゃるかもしれませんが、この場合は(be) foam(ing) at mouthの形で用いられ、「〈狂犬病患者・てんかん患者が〉泡を吹く」（『リーダーズ英和辞典』（第３版、研究社））という意味です。ここは「少女が口から泡を吹いて」という意味で用いられています。LDOCEには”to have bubbles coming out of your mouth because you are ill”と定義されておりました。なるほど、これなら他の病気、あるいは他の症状の人にも用いることができそうですね。(Kawada)
Police looking for man who gave 9-year-old girl tainted candy in park
TOKYO —Police are searching for a man who gave a 9-year-old girl candy that was laced with a powerful sleeping drug, in a Tokyo suburban park on July 29.
The girl collapsed and was foaming at the mouth and in a dazed state when she was found by a passerby in the park in Mizuho town, police said.
Police released the details to the media on Monday. The girl, who has since recovered, was quoted by police as saying that she was playing in Matsubaranishi Park at around 3:30 p.m. when a man she did not know approached her, NTV reported Tuesday. She said the man was very friendly and offered her what she perceived to be candy, and a Calpis drink.
Police said the girl began feeling ill and soon after, collapsed onto the sidewalk where she was found by a passerby. There was no sign of the man who gave her the candy, police said.