Manducatio impiorum ("eating by the impious") or manducatio indignorum ("eating by the unworthy") is the view, held by Martin Luther and Philipp Melanchthon, but denied by Huldrych Zwingli and John Calvin, that even unbelievers who eat and drink the Eucharist eat and drink the body and blood of Christ.   It relates to doctrine of the real presence of Christ in the Eucharist, and in particular to the interpretation of 1 Corinthians 11:27-29:
- Therefore, whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of sinning against the body and blood of the Lord. A man ought to examine himself before he eats of the bread and drinks of the cup. For anyone who eats and drinks without recognizing the body of the Lord eats and drinks judgment on himself.