Enzootic bovine haematuria (EBH) in cattle occurs in upland areas of the world. In India, the disease is present in isolated pockets in the Himalayas and in the Nilgiri Hills. The variation in the disease incidence has been attributed to different environmental conditions and animal rearing practices followed in the different regions. The aim of the study was to conduct field surveys in parts of EBH endemic regions of Himachal Pradesh, a north-western Himalayan state of India. Out of the total 103 plant samples collected, a total of 95 samples were identified as ferns. The major ferns identified included, Onychium japonicum (Thunb.) Kunze, Polystichum piceopaleaceum Tagawa, Dryopteris juxtaposita Christ, Pseudocyclosorus canus (Baker) Holttum and J.W. Grimes, Onychium contiguum C. Hope, Dryopteris nigropaleacea (Fraser-Jenk.), Pteridium aquilinum (L.) Kuhn, Diplazium esculentum (Retz.) Sw., Allantodia maxima (D. Don) Ching, Woodwardia unigemmata (Makino) Nakai, Pteris cretica L., Pteris vittata L., Asplenium trichomanes L., Thelypteris phegopteris (L.) Sloss. ex Rydb, Adiantum venustum D. Don and Paraceterach vestita (Hook.) R.M. Tryon. The concentration of ptaquiloside (PTA) and pterosin B (PtB) in some of the ferns collected from Kullu and Chamba regions ranged from 0 to 358.6 ± 70.5 μg/g and 0 to 652.4 ± 50.0 μg/g, respectively. In addition, field cases of the disease in cattle were also studied in the EBH endemic districts. A total of sixteen cattle urine samples and one urinary bladder of EBH affected cattle were collected. On physical, chemical (benzidine test) and microscopic examination of urine sediment, all the sixteen field samples were found to be positive for erythrocytes and the cases were diagnosed as macrohaematuria. The clinico-pathological studies on the field cases and the presence of PTA and PtB in the ferns indicated that EBH is a prevalent disease and there is an association between chronic fern ingestion and EBH in cattle. On the basis of gross pathology, histopathology and immunohistochemistry (p53 and H-ras nuclear expression in the urothelial cells) of the urinary bladder tissue, the field case was diagnosed as transitional cell adenocarcinoma with chronic lymphocytic cystitis.