四分比丘戒本疏 2.70

2.70

第三十九、不受食戒。「除水及楊枝」者，濁水若楊枝須咽汁者不，在開限也。

Thirty-ninth: The precept on unreceived food. 'Except water and willow twigs': turbid water or willow twigs whose juice must be swallowed do not fall within the exemptions.