[4] After graduating Epps moved back to London where he began to practice, eventually settling in Great Russell Street.

He became Medical Director of the Royal Jennerian and London Vaccine Institution, on the death of John Walker.

There was briefly (1830–31) a medical school in Brewer Street, set up by William Birmingham Costello, Epps and Michael Ryan.

[8] Epps and Ryan then joined George Darby Dermott in giving lectures at the Western Dispensary in Gerrard Street; James Fernandez Clarke, in his memoirs, described Epps lecturing there as well-read and sympathetic but not deeply versed in practical chemistry, or botany.

[1] Introduced to it by his anatomy teacher William Sleigh while still a teenager, Epps embraced the phrenology of Franz Joseph Gall and Johann Spurzheim.

He wrote in his diary "[I have] come to consider all creatures as being equally important in the scale of creation as myself; to regard the poor Indian slave as my brother".

[23] He opposed "Church Rates, war, despots, corn laws, and other old institutions", and enjoyed giving political addresses.

His activism brought him into contact with Joseph Hume, Lady Byron, George Wilson (president of the Anti-Corn Law League), Giuseppe Mazzini, Thomas Slingsby Duncombe, James Stansfeld, Lajos Kossuth, and Robert Owen.

He was an active member of the Anti-Corn Law League and joined organizations in favor of the Polish, Italian, Hungarian, and American nationalities.

[2] From an early age he declared himself an enemy to church establishments and a paid ministry, which can be seen in some of the parliamentary reforms he pushed for.

He also spoke out against the glorification of war-heroes: "the honour of the British flag is a specious phrase which blinds men's eyes to right and wrong", he said.

[2] According to Epps, references in the Bible to the devil and Satan are, in the main, to be understood as personifications of the lustful principle in humans.

[2][28] The publication brought considerable opposition and, according to historian Alan Eyre,' a lecture given shortly afterward to the Tooting Institution at the Mitre Inn in ... London ... caused serious offence and led to widespread ostracism and hostility'.

[2] Similarly, a few years earlier he had delivered a series of lectures at the Dock Head Church to demonstrate that the devil is not a personal being and "this bold assertion drew upon him a world of abuse, and some patients declined to be treated by one holding such heterodox views".

[1] Epps wrote a number of books, starting before he attended university with A New Way of Teaching English Grammar.

[1] He established a journal, Notes of a New Truth, for the propagation to nonprofessionals of the "new school" of homoeopathy, to which he contributed up to the time of his death.