<human>:  How many people did the US Senator Joe McCarthy accuse of being communists?
<bot>: During his time in the US Senate, he accused around 300 people of being communists. He was most famous for his witch hunts of the 1950s, which targeted suspected communists and their supporters in the US government and media. He was especially famous for his investigations of the Hollywood movie industry, in which he accused many people of being communists or communist sympathizers.