Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon II

Canon II.

If any one shall condemn him who eats flesh, which is without blood and has not been offered to idols nor strangled, and is faithful and devout, as though the man were without hope [of salvation] because of his eating, let him be anathema.

Notes.

Ancient Epitome of Canon II.

Anathema also to him who condemns the eating of flesh, except that of a suffocated animal or that offered to idols.

Hefele.

This canon also, like the preceding one, is not directed against the Gnostics and Manicheans, but against an unenlightened hyper-asceticism, which certainly approaches the Gnostic-Manichean error as to matter being Satanic.  We further see that, at the time of the Synod of Gangra, the rule of the Apostolic Synod with regard to blood and things strangled was still in force.  With the Greeks, p. 93 indeed, it continued always in force as their Euchologies still show.  Balsamon also, the well-known commentator on the canons of the Middle Ages, in his commentary on the sixty-third Apostolic Canon, expressly blames the Latins because they had ceased to observe this command.  What the Latin Church, however, thought on this subject about the year 400, is shown by St. Augustine in his work Contra Faustum, where he states that the Apostles had given this command in order to unite the heathens and Jews in the one ark of Noah; but that then, when the barrier between Jewish and heathen converts had fallen, this command concerning things strangled and blood had lost its meaning, and was only observed by few.  But still, as late as the eighth century, Pope Gregory the Third (731) forbade the eating of blood or things strangled under threat of a penance of forty days.

No one will pretend that the disciplinary enactments of any council, even though it be one of the undisputed Ecumenical Synods, can be of greater and more unchanging force than the decree of that first council, held by the Holy Apostles at Jerusalem, and the fact that its decree has been obsolete for centuries in the West is proof that even Ecumenical canons may be of only temporary utility and may be repealed by disuser, like other laws.

This canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars I., Dist. XXX., c. xiii.