SENTENCE: “The ministry of health warns from the consumption of melon fruits”
My colleagues and I are debating whether or not “warns from” is grammatically correct. I googled the phrase and although, “warned about”, “warned of”, and “warned against” popped up, “warns from” never did. But I’m thinking, maybe it’s just not colloquially used but still grammatically correct?
In a Google NGram querying for warned from, results prior to ca. 1900 suggest a meaning similar to the one you’re asking about. Your suspicion that the usage, while strictly grammatical, is archaic has proven to be correct.
An NGram queries the Google Books corpus, the earliest volumes mostly supplied by university libraries and then augmented by more contemporary printed sources which may include more popular, ephemeral literature. They are thus a more accurate, chronologically ordered measure of usage then a mere internet search.
…or if that condition shall not like your grace, yet that then he [a Catholic chaplain] may be warned from your grace’s house, and not kept there, to be as it were defended from the power of the law. Letter from the Council to Lady Mary, 25 Dec. 1550
But, alas! the waters were too gelatinous to flow, or were enveloped in their own membranes, forming hydatids, which we were, by former experience, warned from meddling with. Medical Repository, 1805.
Warned from this unholy sojourn, [joining a band of buccaneers] by the imagined voice of his murdered wife, he returns home… The Monthly Review, 1813.
May his holy and purifying fear, which endures for ever, be deeply grafted in our hearts, that we may stand in awe of his righteous judgments, and be warned from every evil way … Thomas Scott, The Holy Bible, with Explanatory Notes…, 1822.
We daily hear that persons are warned from associating with us, as with those infected with the plague … English trans. of The Works of Friedrich Schiller, 1851.
By the twentieth century, the verb to warn had lost its ablative force of warning away from and instead took other prepositions. Results after around 1900 are either false hits — “He warned, ‘From now on…'” — or a warning issued from a particular place — “warned from London”— or time — “warned from the beginning.” An author can also be citing a much older source, such as the letter to the future Queen Mary.
So unless you want to sound like someone from the nineteeth century or have no investment in using constructions your readers will readily understand, you are best advised to construct a sentence using one of the prepositions currently used with the verb to warn.