In this new and largest echinacea study to date, 755 healthy people took echinacea or a placebo. The dose was 800 mg of echinacea liquid extract three times per day, or during colds, five times per day. After four months, compared to placebo, the echinacea group had 20 percent fewer colds with symptoms clearing up 20 percent quicker, and 35 percent fewer recurrences. Those taking echinacea also had fewer flu-type viral infections and needed less over-the-counter medication such as acetaminophen or ibuprofen. To reduce and prevent colds and flu, doctors said this study adds evidence that echinacea can help.