Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Lettuce in a dream indicates a man who appears good but is bad inside. Eating it indicates illness.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Lettuce indicates goodness and benefit. It is healing from illnesses.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Lettuce is interpreted as goodness. Whoever sees himself eat it will receive goodness.