Do unsavoury armpits and bad breath make you angry? What good will it do you? Given the mouth and armpits the man has got, that condition is bound to produce those odours.
“After all, though, the fellow is endowed with reason, and he is perfectly able to understand what is offensive if he gives any thought to it.”
Well and good: but you yourself are also endowed with reason; so apply your reasonableness to move him to a like reasonableness; expound, admonish. If he pays attention, you will have worked a cure, and there will be no need for passion; leave that to actors and streetwalkers.

[Τῷ γράσωνι μήτι ὀργίζῃ, μήτι τῷ ὀζοστόμῳ ὀργίζῃ; τί σοι ποιήσει; τοιοῦτον στόμα ἔχει, τοιαύτας μάλας ἔχει, ἀνάγκη τοιαύτην ἀποφορὰν ἀπὸ τοιούτων γίνεσθαι.
— ἀλλ̓ ὁ ἄνθρωπος λόγον ἔχει, φησί, καὶ δύναται συννοεῖν ἐφιστάνων τί πλημμελεῖ.
— εὖ σοι γένοιτο: τοιγαροῦν καὶ σὺ λόγον ἔχεις, κίνησον λογικῇ διαθέσει λογικὴν διάθεσιν, δεῖξον, ὑπόμνησον: εἰ γὰρ ἐπαίει, θεραπεύσεις καὶ οὐ χρεία ὀργῆς.
Οὔτε τραγῳδὸς οὔτε πόρνη.]

Marcus Aurelius (AD 121-180) Roman emperor (161-180), Stoic philosopher
Meditations [To Himself; Τὰ εἰς ἑαυτόν], Book 5, ch. 28 (2.5) (AD 161-180) [tr. Staniforth (1964)]
    (Source)

This chapter can be interpreted a couple of different ways, as the various translations indicate. The most straightforward is to not be angry over an offense that cannot be avoided; if someone can be reasoned out of being offensive, then use reason, not anger. Don't be a drama queen.

To make things more clear, I have added the paragraph breaks that a couple of the translators used to the original and all the translations.

Long notes the last part of this passage (about "actors and harlots") is corrupted in some way and cannot be rendered sensibly. Farquharson calls the four words "one of the unsolved enigmas of our book," and notes Gataker's interpretation that a good man neither dramatically lauds it over a bad one, nor panders to them. Some translators leave the passage out; others try to find a meaningful way to integrate it; most modern ones simply quote it translate it and leave it as a fragment.

(Source (Greek)). Alternate translations:

Be not angry neither with him whose breath, neither with him whose arm holes, are offensive. What can he do? such is his breath naturally, and such are his arm holes; and from such, such an effect, and such a smell must of necessity proceed.
"O, but the man (sayest thou) hath understanding in him, and might of himself know, that he by standing near, cannot choose but offend."
And thou also (God bless thee!) hast understanding. Let thy reasonable faculty, work upon his reasonable faculty; show him his fault, admonish him. If he hearken unto thee, thou hast cured him, and there will be no more occasion of anger.
[tr. Casaubon (1634), 5.22]

Are you angry at a Rank Smell, or an ill scented Breath? Why if a Man's Lungs, or Stomach, are ulcerated, or his Arm-pits out of Order, how can he help it.
But you'll say, the case is not parallel, between an ill Action, and an ill Breath; the one is Choice, and the other Necessity.
Well, If you think Mankind so full of Reason, pray make use of your own: Argue the Case with the Faulty Person, and show him his Error: If your Advice prevails, he is what you would have him; and then there is no need of being angry: And lastly, Don't mismanage either by your Haughtiness, or Servility.
[tr. Collier (1701)]

Can you be angry at one, whose arm-pits or whose breath are disagreeable? How can the man help it, who has such a mouth or such armpits? They must have a smell.
But, says one, man has reason: he could by attention, discern what is injurious in his actions; [these may justly raise anger.]
Well, God bless you, you have this reason too. Rouse then his rational dispositions, by your rational dispositions; instruct, suggest to him, what is right. If he listens to you, you have cured him, and then there is no occasion for anger. Let us have no tragical exclamations against the vices and injuries of others; nor a base concurrence with them, like that of harlots.
[tr. Hutcheson/Moor (1742)]

Would you quarrel with a man who had the misfortune to have a bad breath, or any other natural infirmity? If his lungs or his constitution necessarily produce those effects, how can he avoid it?
But, you will say, "It is not a parallel case between a bad breath and an ill action. The man, in the latter case, being endued with reason, might know and avoid acting ill."
Well, Sir, you are a happy man; and, as you always act rationally, endeavour to excite the same laudable disposition in your friend: Shew him his error, and admonish him; if he listens to your advice, you will cure him of his fault, and there will be no room for your anger. Do not make too serious an affair of it; nor yet encourage him in his faults by a meretricious compliance.
[tr. Graves (1792)]

Art thou angry with him whose armpits stink? art thou angry with him whose mouth smells foul? What good will this anger do thee? He has such a mouth, he has such armpits: it is necessary that such an emanation must come from such things:
but the man has reason, it will be said, and he is able, if he takes pains, to discover wherein he offends;
I wish thee well of thy discovery. Well then, and thou hast reason: by thy rational faculty stir up his rational faculty; show him his error, admonish him. For if he listens, thou wilt cure him, and there is no need of anger.
[Neither tragic actor nor whore.]
[tr. Long (1862)]

Are you angry at a rank smell or an ill-scented breath? What good will this anger do you?
But you will say, the man has reason, and can, if he takes pains, discover where in he offends.
I wish you joy of your discovery. Well, if you think mankind is so full of reason, pray make use of your own. Argue the case with the faulty person, and show him his error. If your advice prevails, he is what you would have him; and then there is no need of being angry.
[tr. Collier/Zimmern (1887)]

Do you get angry at rank armpits? or at foul breath? What would be the good? Mouth, armpits are what they are, and being so, the given effluvia must results.
-- "Yes, but nature has given man reason, man can comprehend and understand what offends!"
-- "Very good! Ergo you too have reason; use your moral reason to move his; show him his error, admonish him. If he attends, you will amend him; no need for anger -- you are not a ranter, or a whore."
[tr. Rendall (1898)]

Are you angry with one whose armpits smell or whose breath is foul? What is the use? His mouth or his arm-pits are so, and the consequence must follow.
But, you say, man is a reasonable being, and could by attention discern in what he offends.
Very well, you too have reason. Use your reason to move his; instruct, admonish him. If he listens, you will cure him, and there will be no reason for anger. You are neither actor nor harlot.
[tr. Hutcheson/Chrystal (1902)]

If a man's armpits are unpleasant, art thou angry with him? If he has foul breath? What would be the use? The man has such a mouth, he has such armpits. Some such effluvium was bound to come from such a source.
But the man has sense, quotha! With a little attention he could see wherein he offends.
I congratulate thee! Well, thou too hast sense. By a rational attitude, then, in thyself evoke a rational attitude in him, enlighten him, admonish him. If he listen, thou shalt cure him, and have no need of anger.
Neither tragedian nor harlot.
[tr. Haines (Loeb) (1916)]

Are you angry with the man whose person or whose breath is rank? What will anger profit you? He has a foul mouth, he has foul armpits; there is a necessary connexion between the effluvia and its causes.
"Well, but the creature has reason, and can, if he stops to think, understand why he is offensive."
Bless you! and so too have you reason; let reasonable disposition move reasonable disposition; point it out, remind him; for if he hearkens, you will cure him and anger will be superfluous. You are neither play-actor nor harlot.
[tr. Farquharson (1944)]

You are angry with a man if he smells of stale sweat, or has bad breath? What good will it do you? He has such a mouth, he has such armpits; and being as they are, such exhalations are bound to arise from them.
"Yes, but the man is endowed with reason, and if he would only think, he could see why he is out of line."
Gracious me, you have reason too, so set his powers of reason to work by making use of your own! Show him his fault, call it to his attention; for if he listens, you will cure him, and there will be no need for anger.
Neither a play-actor nor a prostitute.
[tr. Hard (1997 ed.)]

Don’t be irritated at people’s smell or bad breath. What’s the point? With that mouth, with those armpits, they’re going to produce that odor.
— But they have a brain! Can’t they figure it out? Can’t they recognize the problem?
So you have a brain as well. Good for you. Then use your logic to awaken his. Show him Make him realize it. If he’ll listen, then you’ll have solved the problem Without anger.
Neither player-king nor prostitute.
[tr. Hays (2003)]

Are you angry with the man who smells like a goat, or the one with foul breath? What will you have him do? That’s the way his mouth is, that’s the way his armpits are, so it is inevitable that they should give out odours to match.
"But the man is endowed with reason," you say, "and if he puts his mind to it he can work out why he causes offence."
Well, good for you! So you too are no less endowed with reason: bring your rationality, then, to bear on his rationality -- show him, tell him. If he listens, you will cure him, and no need for anger.
Neither hypocrite nor whore.
[tr. Hammond (2006)]

You are angry with a man if he smells of stale sweat, or has bad breath? What good will it do you? He has such a mouth, he has such armpits; and being as they are, such exhalations are bound to arise from them.
"Yes, but the man is endowed with reason, and if he would only think, he could recognize his fault."
Gracious me, you have reason too, so set his powers of reason to work by making use of your own! Show him his fault, call it to his attention; for if he listens, you will cure him, and there will be no need for anger.
Neither a play-actor nor a prostitute!
[tr. Hard (2011 ed.)]

Surely you aren't angry with someone who smells of stale sweat? Surely you aren't angry with someone with stale breath? What good will that do? That's the kind of mouth he has; that's the kind of armpit he has; and there is a necessary connection between the smells and those factors.
"But this person possesses rationality, and if he gives it thought he can work out why he is offensive."
Well done! So you have rationality too. Activate one rational disposition by another: show him, tell him. If he listens, you will cure him and there will be no need for anger.
Neither a play-actor nor a prostitute.
[tr. Gill (2013)]