Neurocysticercosis (NCC) is the infection of the human nervous system by the larvae of the pork tapeworm Taenia solium. Subarachnoid neurocysticercosis (SANCC) accounts for 20-35% of all NCC cases. It is an aggressive, progressive and frequently lethal presentation of NCC, endemic in most non-Muslim developing countries. Unlike intraparenchymal disease (where the predominant manifestation is seizures and epilepsy, and parasites are located in the brain tissue), in subarachnoid disease the presence of the parasitic masses in the surroundings of the brain, their growth, and the concomitant inflammatory process lead to mass effect, intracranial hypertension and/or hydrocephalus, resulting in heavy morbidity and significant mortality which can be more than 20%. The response to antiparasitic treatment in SANCC is usually slow and partial, but if complete parasite resolution is obtained patients may be cured without further symptoms. This application naturally expands the scope of and applies the knowledge obtained from a recent NINDS-funded trial on combined albendazole (ABZ) plus praziquantel (PZQ) treatment of intraparenchymal NCC [R01 NS054805]. The current treatment regimens for SANCC have quite limited efficacy and the disease is still associated with significant mortality in many places of te world. Combining ABZ and PZQ, along with appropriate steroid coverage and other safety measures, is the logical next step to improve the management of subarachnoid NCC and has not been examined before in a controlled trial. In this double-blind, randomized, placebo-controlled study, 164 patients with subarachnoid cysticercosis of the basal cisterns or the Sylvain fissure, will be assigned to either the standard of care anti- parasitic regime (30-day ABZ at 15 mg/k/d) or a combined regime adding PZQ at 50 mg/k/d for the initial 15 days of anti-parasitic treatment. The primary study endpoint is the proportion of patients with disappearance of their parasitic lesions in neuroimaging at six months after therapy onset. Secondary outcomes include the decrease in volume of parasitic masses measured by MRI at 3 and 6 months after treatment onset, clinical improvement evaluated as the proportion of patients asymptomatic and without need for further antiparasitic treatment 6 months post-treatment, the frequency of serious adverse events (SAE) of the combined regime compared to the standard of care, the decrease in the serum levels of circulating parasitic antigen at 3 and 6 months after treatment onset, and the proportion of patients whose lesions resolve and do not relapse by 12 months after treatment onset. The trial will initially involve four centers: two in Peru, one in Brasil and one in Ecuador with the potential to expand to more centers if required. By comparing two active regimes, the proposed parallel group design permits open assessment of control neuroimaging scans for patient safety without affecting treatment blinding, and will provide the first data to support either therapeutic change or maintenance of the standard of care. If this tril succeeds, it will provide a new, more appropriate standard of care, available worldwide.