On December 9, 2020, Dallas County Health and Human Services (DCHHS) was notified of a hospitalized male, aged 33 years (patient A), who was experiencing homelessness and had bilateral ptosis, upper and lower extremity weakness, and respiratory failure requiring intubation. The patient reported injecting methamphetamines, and physical examination noted track marks but no overt skin wounds or abscesses. Patient A was treated with naloxone. Heroin and methamphetamines were detected in the patient’s urine. Myasthenia gravis was initially suspected; however, botulism was considered when the patient did not respond to treatment with pyridostigmine and steroids and the patient’s weakness continued to progress. DCHHS contacted the Texas Department of State Health Services (DSHS) and CDC’s botulism clinical consultation service.* Heptavalent botulinum antitoxin (BAT) was released by CDC on December 9, 2020, and administered to the patient on December 10. Botulism testing results were not available before treatment with BAT. Botulism neurotoxin (BoNT) types A and B were detected in the patient’s serum specimen using the BoNT Endopep-MS assay (1).