European stocks fell the most in 11 weeks as health care companies tumbled amid concern tougher American tax rules will erode their takeover appeal and as manufacturing growth slowed in the euro area. All the 19 industry groups on the Stoxx Europe 600 Index declined. Shire (SHPG) and AstraZeneca (AZN) each lost more than 2% after the U.S. made it harder for companies to move their tax base abroad.