There is suggestive evidence that vitamin C and vitamin D deficiency may increase blood pressure across the range of blood pressures from normal to elevated. Information about this relationship is inadequate in part because of the rarity of individuals with subclinical vitamin C and D deficiency. The investigators have observed subnormal to deficient plasma vitamin C and 25-hydroxyvitamin D levels in a large proportion of patients under active treatment in the investigators' hospital. The clinical implications of widespread hypovitaminosis C and D are unknown. In this randomized prospective comparison trial the investigators will measure vitamin levels and blood pressure in clinically stable acutely hospitalized patients with a wide range of diagnoses, and expected to remain in the hospital for at least 7 more days. The investigators will examine for an inverse relationship between baseline vitamin level and blood pressure across the range of blood pressures. Consenting patients will be randomized to receive vitamin C (500 mg twice daily) or vitamin D (1000 IU twice daily) for as long as 10 days. Blood pressure will be re-measured every 2 days and vitamin levels re-measured on the last study day. Treatment courses of at least 5 days will be considered sufficient for analysis. The hypothesis is that either treatment will reduce blood pressure in patients whose baseline systolic blood pressure is 110 or more; the investigators will also examine whether the reduction in blood pressure with treatment is proportional to the increase in the circulating vitamin level with treatment.

Inclusion Criteria:

• Competent to grant informed consent
• Anticipated to remain in hospital at least 7 days after enrollment

Exclusion Criteria:

• End-stage renal disease on renal replacement therapy
• Critical illness
• Judged unstable clinical status at the time of enrollment