When prescribing lithium, the risk of toxicity remains a concern. In this study, we examined a cohort of patients exposed to lithium between 1997 and 2013. The aims of this study were to determine the frequency of lithium intoxication and to evaluate the clinical course and changes in renal function. Of 1340 patients, 96 had experienced at least one episode of lithium levels ⩾1.5 mmol/L, yielding an incidence of 0.01 per patient-year. Seventy-seven patients available for review had experienced 91 episodes, of whom 34% required intensive care and 13% were treated with haemodialysis. There were no fatalities. Acute kidney injury occurred, but renal function at baseline was not different to renal function after the episode. Renal impairment was often associated with co-morbidities and other factors. Both intermittent and continuous-venovenous haemodialysis were used, but the clearance of continuous-venovenous haemodialysis can be too low in cases where large amounts of lithium have been ingested. Saline and forced diuresis have been used and are safe. Lithium intoxication seems rare and can be safely managed in most cases. Physicians should not withhold lithium for fear of intoxication in patients who benefit from it. Yet, physicians should have a low threshold to screen for toxicity.