Short answer. The Labor Code sets ten days from notice for an aggrieved party to seek review on certiorari by the Supreme Court, on questions of law only. That period is very short. In practice the route and the reglementary period are governed by the Rules of Court, so take advice immediately rather than assuming ten days.
What the law says
Decisions, orders or resolutions of the Commission may be reviewed on certiorari by the Supreme Court on question of law upon petition of an aggrieved party within ten (10) days from notice thereof.
Labor Code, Article 181 — Review By The Supreme Court. Read the full provision →
What the article allows, and what it does not
Two limits matter as much as the ten days. First, review is on question of law — the Court is not asked to re-weigh the medical reports, the employment records, or the credibility of witnesses. If the real complaint is that the Commission got the facts wrong, that is not what this remedy is for. Second, only an aggrieved party may petition, meaning someone whose rights the decision actually affects. A relative who is unhappy with the outcome but has no claim of his own is not an aggrieved party in that sense.
Counting the ten days
The clock runs from notice thereof — from when the decision was received, not from when it was signed, and not from when you happened to read it. Keep the envelope, the registry receipt or the transmittal, because the date of receipt is the fact everything else turns on. If a motion for reconsideration is available and you file one, the effect on the period is a technical question you should not guess at. Missing the period is not a formality: once the decision becomes final, no court will look at its merits, however strong they were.
The statute is not the whole picture
This provision was written before the present Rules of Court took their current shape, and court procedure is now governed by those Rules rather than by the Labor Code alone. Decisions of quasi-judicial agencies are ordinarily brought to the Court of Appeals by petition for review under Rule 43, which carries its own reglementary period, and the Supreme Court is reached only afterwards. Filing in the wrong court, or by the wrong mode, is one of the commonest ways a good claim is lost, so the choice of remedy has to be made before the deadline, not after.
What to do this week
Find the date of receipt and work backwards from it before anything else. Get a certified copy of the decision and the complete record of the proceedings below, since a petition stands or falls on the record. Write down, in one page, exactly which legal error you say was committed — a misreading of the statute, a finding made with no evidence at all, a denial of the chance to be heard — because a petition that merely disagrees with the result will not get far. Then see a lawyer at once; the period is measured in days, not weeks.