This paper examines a preference among rural Catholics in Northeast Brazil to treat generalized forms of malaise with isotonic solution administered intravenously, even where such treatment goes against biomedical advice. It situates this practice within a nexus of local ideas about the value of blood and sacrifice, which emerge out of socio-historical and environmental factors particular to the region. In this context blood is merely one in a sequence of substances linked to the regenerative martyrdom of Jesus, to the agricultural cycle, and to the economic struggle for existence in a drought-affected region. The materialization of blood, sweat, and tears on the surface of the body indexes social relationships built on sacrifice. The appearance of such substances, often between categories of close kin, are ideally characterized by the loss or flow of substance in a single direction. In such contexts replenishing the blood with isotonics maintains a uni-directional flow, preserving the value of sacrifice.My mouth is dried up like baked clay ... you have brought me down to the dust of death.Psalm 22:16It was clinic day at the health post in the village of Santa Lucia; it happened every fifteen days. The brick building designated as the health post consisted of a single, rectangular room. Towards one end a faded cotton curtain separated the waiting area from the visiting doctor, Dr Renato, 1 who sat behind a laminate table. In a corner of this consultation area was a cupboard holding two cardboard boxes: one containing plasters, bandages, and antibacterial solutions; the other containing intravenous tubes, hypodermic needles, and packets of soro -sterile isotonic fluid. The clinic had barely begun but already the waiting area was full with patients. There were two assistants working with Dr Renato that morning: Rita, the nurse, and Lia, a general assistantcum-receptionist. Both women lived in the village, and between them and Dida, the health post cleaner, the clinic was kept clean and in good working order. It was Dida who held the keys to the building and she who, every fifteen days, would leave home early in the morning to unlock the door and prepare the space for the doctor's arrival. During fieldwork I was a regular attendee at the village clinic. Conversing with people in the waiting room was a good way to pass the hours. On this particular occasion I was greeted, somewhat unusually, by the sight of Lia, sitting at the receptionist's desk, and being hooked up to an isotonic drip. Rita, the nurse, was adjusting bs_bs_banner