Determination of arsenic (As) in animal feed chain and its products and the efficacy of Spirulina (Spirulina platensis) against arsenic-induced toxicity in goats were studied. Urine, dung and milk from cows, tissues and excreta from broilers, eggs and excreta from laying hens and as a potential source of As contamination, drinking water, rice straw and poultry feed were collected from five As-prone areas of Bangladesh. Adult non-pregnant Black Bengal goats (Capra hircus) were allocated into three groups as T1 (n = 4), T2 (n = 8) and T3 (n = 16). T2 and T3 were orally administered sodium arsenite (5 mg kg-1) daily for 15 weeks. T3 was then divided into four equal sub-groups and Spirulina was fed to three sub-groups @ 50, 100 and 150 mg kg-1 daily for a further 15 weeks, one sub-group being a control (+). Body weights were recorded weekly and goats were euthanized after termination of As (T1 and T2) and Spirulina (T3). Blood, urine, faeces, hair and hoof-parings were collected every three weeks and tissues after euthanasia for determination of As, biochemical parameters, histopathology, immunohistochemistry and folliculogenesis. As concentration in cows' drinking water, rice straw (dry weight; DW), urine (specific gravity adjusted to 1.035), dung (DW) and milk (wet weight; WW) were 89.6±6.5, 1114.4±57.3, 123.6±7.6, 1693.0±65.1 and 26.2±2.8 ppb, respectively. Significantly (P<0.01) higher As was in Boro straw (1386.9±71.8 ppb) than Aus (702.4±67.1 ppb) and Aman (431.7±28.8 ppb), and in straw irrigated with shallow well water (1697.3±81.9 ppb) than that of deep well water (583.6±62.7 ppb) and surface water (511.8±30.0 ppb). As concentration in broilers' drinking water, feed (DW) and excreta (DW) were 80.4±5.5, 119.0±4.7 and 1221.8±58.3 ppb, respectively. In broiler tissues (WW), the highest concentration of As was in skin (218.8±11.7 ppb), followed by liver (102.1±8.0 ppb), lung (96.3±5.6 ppb), kidney (88.2±7.5 ppb) and thigh muscle (67.8±5.1 ppb). As concentrations in the drinking water, feed (DW), eggs (WW) and excreta (DW) of laying hens were 77.3±5.4, 176.6±8.0, 19.2±1.2 and 1439.9±60.3 ppb, respectively. As content in drinking water and feed were positively correlated with As residues in dairy and poultry products. Compared to controls, goats fed sodium arsenite had higher As efflux through metabolic pathways and accumulation of As in organs with highest residue in kidney. The As-treated goats exhibited an increase in serum activities of alkaline phosphatase (ALP), aspartate aminotransferase (AST), creatinine, total bilirubin and triglyceride (TG); elevated malondialdehyde (MDA) levels in liver and kidney tissues; aggravated histoarchitectures of liver, kidney, urinary bladder, skin and heart; reduced diameters of primordial and primary follicles, thickened granulosa layer of antral follicle. But numbers of ovarian follicles (primordial, primary, secondary and antral), IgG and IgM-bearing lymphocytes in lymph nodes and spleen were not affected by As exposure. Depletion of As residues in blood, urine and faeces followed As withdrawal; but in hair the value elevated for a short period, thereafter decline slowly and in hoof-parings there was a linear increase with time. After As withdrawal serum concentrations of ALP, AST, creatinine, total bilirubin; As residues in tissues and histoarchitecture of urinary bladder reverted to previous state but slight histopathological lesions remained in liver, kidney, skin and heart. Spirulina feeding improved weight gain and restored MDA values, but did not have significant effects on As efflux through the blood, urine, faeces, hair and hoof; the rate of diminution of As residues from tissues; the restoration of biochemical values; the histoarchitecture of tissues. IgG and IgM-bearing lymphocytes remained unaltered by Spirulina supplementation. These results provide evidence that though high As prevails in Bangladesh drinking water; the As content in broiler meat, eggs and milk were below the maximum tolerable limits for humans. However, As in food and/or drinking water makes a significant contribution to the As accumulations in poultry and dairy products. Low sub-chronic exposure of As had little effect on goats, especially in terms of their biochemistry. Spirulina increased weight gain and depleted As-induced MDA levels in goats.