Separation Anxiety Syndrome (SAS) in dogs has been one of the most common post-Covid-19-pandemic behavioral disorders, which usually presents destructive and aggressive behavior, excessive barking, urinating and defecating in inappropriate places, vomiting, anxiety, frustration, panic, fear, boredom and aggressiveness as some of the clinical signs. Treatment usually consists of environmental enrichment, behavioral training, allopathic treatment with anti-depressives, anxiolytics and integrative treatments such as Plactiplantibacillus plantarum PS128, the herbal medicine Ashwagandha, homeopathy and acupuncture. We present the clinical case of a male dog, Brazilian terrier breed, who showed separation anxiety when his tutors returned to work after the isolation brought on by the covid-19 pandemic; the dog has also presented seizures every-3-4 months and grade 3-4 periodontal disease. After repertorization, treatment with Arsenicum album 30 CH twice a day was instituted for 30 days for separation anxiety. For periodontal disease, Mercurius solubilis 6CH three times a day for 30 days and, for seizure crises, Cicuta virosa 200 CH once a week until further recommendations. After returning at 30, 60, 90 and 120 days for re-evaluation, noteworthy improvement in anxiety behavior was reported, as well as spacing in seizure episodes. The homeopathic medicines instituted in this clinical case report demonstrated effectiveness in the treatment of behavioral disorders, as well as the physical signs.