It is narrated from Sayyidah Aishah (may Allah be pleased with her) that she said: I fell ill, and my family made me abstain from everything, even water. One night I became very thirsty and no one was with me. I went near a hanging waterskin and drank a sip of water from it. In the morning I got up completely healthy, and I could feel the blessing of that one sip in my body. Sayyidah Aishah (may Allah be pleased with her) used to say: "Do not make the sick person abstain (strictly) from anything." This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.