Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Basil (Rayhan) in a dream indicates a child, knowledge, or a wife. For the sick, it is healing, and for the worried, relief.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Basil indicates good speech and good praise. Smelling it indicates comfort and joy.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Basil is interpreted as a righteous son. Picking it indicates a small worry followed by joy.