Dies Sanguinis (Day of Blood) was a festival held in Ancient Rome on 24 March. Also known as Bellona's Day, this was an occasion when the Roman votaries of the war-goddess Bellona cut themselves and drank this sacrificial blood to propitiate the deity.
The priests of the goddess Cybele (the galli) flogged themselves until they bled and sprinkled their blood upon the image and the altars in the sanctuary, while others are said to have imitated Attis by castrating themselves.However. Roman citizens were forbidden from engaging in self-castration, so in time the Galli were all non-citizens. Such painful and dramatic acts allowed the worshipers to identify with the pain and death of Attis, to whom were dedicated a cycle of festivities, which were celebrated from 15 to 28 March.
The Priest of Bellona (also known as Bellonarii) practiced other rituals on Dies Sanguinis, one rite being to mutilate their own limbs, such as their own arms and legs with a sharp knife or knives in order to collect their own blood to either drink, or offer to their goddess Bellona in order to get her to invoke her war fury on them.
There also a plant known as the Bellonaria plant (solanum). Which is a corruption on the name Belladonna, a deadly nightshade, was used by priests at this festival, Dies Sanguinis. When a priest ate its seeds, they would start to hallucinate. Those hallucinations were used by them to make prophetic and oracular statements in the name of their goddess.
These festivities celebrated the death of the god. Among these, there were the "Sanguem" and the "Hilaria". The Hilaria on 25 March brought renewed joy and hope. There was feasting in honor of the Great Mother, Cybele, and good cheer.
The spring festival came to a close with a much-needed day of rest (March 26) and a final day (March 27) on which the holy image of the Great Mother was bathed in the Almo River.