Ascorbic acid (vitamin C) is relevant to forensic science primarily because of its chemical reactivity: it is a strong reducing agent and antioxidant that can alter commonly used analytical reactions and the stability of biological markers. High concentrations of ascorbic acid are known to interfere with colorimetric and peroxide-based assays and with some potentiometric measurements, producing false increases or decreases in routine clinical-chemistry results and reducing chromogen signals used in automated tests; this same redox chemistry explains why vitamin C can delay or mask presumptive blood tests such as leucomalachite green for latent stains.

There are a handful of forensic-relevant clinical/toxicology reports linking extreme vitamin C intake to harm: although ordinary dietary doses are safe, very large or prolonged doses have been associated with oxalate nephropathy and renal failure (including at least one fatal report), and hypervitaminosis C can produce metabolic or lab artifacts that complicate interpretation of postmortem biochemistry. For forensic toxicologists this means (a) declaring and accounting for vitamin supplementation when interpreting metabolic derangements, and (b) being cautious with analyte results that are susceptible to redox interference.

Ascorbic acid is widely used as a food additive/preservative and its presence matters in food-forensics and postmortem investigations for two reasons: it can mask or complicate detection of oxidizable poisons or adulterants, and its stability (and measured decline after death or during storage) has been explored as a potential marker in postmortem interval and food-spoilage studies. Practical forensic work therefore uses robust, selective methods (HPLC or LC–MS/MS) to quantify vitamin C and its degradation products, considers matrix-matched controls, and documents supplementation or preservative use when reconstructing exposures or interpreting toxicology and food-adulteration cases.