As a happy-go-lucky drifter, Professor McGargle, accompanied by his daughter, arrives in a country town.  Quickly the Professor establishes himself as the prize medicine-selling star of a traveling carnival.  Meanwhile, his daughter Poppy meets and falls in love with Mayor Farnsworth's son Billy.  The charm of this is balanced by the menace to the Professor of gabby Countess De-Puizzi, masquerading as heir to the Putnam estates and fortunes.  In connivance with a hick lawyer, Whiffen, the Professor sets Poppy up as a claimant for the estate, convincing the Mayor-executor that she is the legitimate heir.

But Poppy encounters romantic troubles with Billy and some that threaten to be more serious crop up for the Professor as Whiffen, teaming up with the Countess, introduces a double-cross.  As things look dangerous to both, kindly Sarah Tucker, who has befriended Poppy, recognizes the resemblance between the child and the deceased Mrs. Putnam.  Forced to make a clean breast of his history, the Professor tells how he had adopted Poppy years ago and that he knew all along that she was the rightful claimant.  This dismays Whiffen and the Countess, who is now revealed as a showgirl.  The finale is thus a happy ending for the Professor, Poppy, and Billy.

What was said about Poppy:

The Listener (Alistair Cooke)
He wanders through small shops and circuses, public bars, children, sideshows, straw hats and nagging women with a bemused aloofness that makes him in this life but not of it.  He's Racchus dropped from the clouds and made to work in the corner grocer's.  He has every decent human motive and would almost choose to act out an honest life, but around him he sees small-timers cheating each other all the way.  That wouldn't distress him either if there was any style to their tricks.  But people are so mean and clumsy he feels obliged to give them a lesson or two, an accomplished robbery here, a short bargain there, done with enough flourish to give the human game some dignity.  He'll try any roguery once, just to feel the thrill of the gestures, just to feel superior to the morons who suspect him.  But he never hopes to win anything.  Except at the end of the film he does.  It  has been Fields' great and individual improvement on the Chaplin pathetic ne'er-do-well that instead of fading away up a lonely road poor but blithe, he ends by winning decisively for the first time in his life.

In It's a Gift he goes through endless squabbling failures to get across the continent and claim an orange grove that turns out to be a shambles.  But a man comes along and offers him a fortune for the land as a building site.  And the last shot was Fields leaning back, in a seersucker suit and a neatly pinned tie, fanning himself in the sun and downing a highball.  In Poppy, he begins promisingly by selling his talking dog and not unnaturally taking the voice away with him, but then after much intermediate wrangling with the poor fools ("Who will be the next to outwit me?  This is a game of chance"), he ends by going off with the Mayor's hat, rather silkier than his own, and a fistful of the Mayor's cigars.  It was cruel that Mr. Bernard Shaw should be asking for "better voices" and good diction on the screen the week that Fields came along.  For he stands as a convenient symbol of the war between the stage and screen, between "fine speaking" and ordinary day-to-day thinking aloud.  He plays with two voices-a smooth, pompous, trained voice and a mumbling, bemused one.  And, not to take sides too openly, I should say he uses the first, the overripe voice, for all his artifice, all the public occasions when he's trying to swindle somebody or claim a family tree.  But he's always caught out by the second voice, by his muttered suspicion that this sort of thing has happened before in the world's history.  He may with a fine flourish of hand and elbow say, "I have here, gentlemen, a very fine timepiece that cost five hundred dollars, yes sir, five hundred dollars," and you can hear him saying under his breath, "you'll never get away with it."
 

Every time he tries to be an actor, horse sense whispers in his ear.  Every time his first voice tries to deceive other people, his second is telling him out of the corner of his mouth that he's kidding nobody but himself.  It doesn't matter much if you don't even catch what the second voice is saying.  It's simply nervous speech with, I'm afraid, Mr. Shaw, definitely bad diction—it's Everyman's misgivings, second thoughts, delayed humility.  In Poppy, it happens to be the language of W.C. Fields, an American juggler.  Ideally, it's the common language of all Cockneys, and French taxi-drivers, and Texas cattlemen, and all simple men permanently impressed by the irony of human dignity.  It's a precious language that belongs more to the movies than to any other form of deception.  For it's the phonetic equivalent of a sense of fact.  And when the screen takes Mr. Shaw's advice and doctors its voice, it can say goodbye to most of the virtues the screen can still claim over a theater resonant with a clatter of consonants and coy scruples.  I'll sit through the movies just as long as the natural voice is accepted as the standard.  The day Gary Cooper gets busy with his diction, I shall take to a tricycle.

The Hollywood Reporter
It is artful nonsense from a master of mad-waggery.

Hollywood Daily Variety
Slow and lacking smoothness, Poppy needs straightening out before it will please many other than out-and-out W.C. Fields fans.

The Literary Digest
Poppy is the motion-picture W.C. Fields almost didn't make.  It is the picture no other clown in Hollywood could have made.  Fields put his trade-mark on the role twenty years ago when he turned the jumble-shop stage show of the same name into a comedy triumph.  Then he made a silent film version.  The present talking-singing version is all that any Fields addict could ask.  When Paramount first considered the picture last winter, Fields didn't think he would live to see a camera turn; and he didn't care.  Gravely ill, weak as a cat, the comedian went out to the desert; he spent weeks there letting the sun bake strength back into him.  When the picture started, he came back to town.  Even then he told friends he'd be lucky to finish it.  None of that siege will be apparent to audiences.  The Fields unction, the Fields serio-comic posturing, run through almost every foot of Poppy.  The plot of the gay, romping insanity is about as mysterious as a cobblestone and just about as old-fashioned.  No one will resent it for that.  It is good antique hokum trussed up for a Fields vehicle. All that matters is that Professor Eustace McGargle is back in perfect form.